TY - JOUR A1 - Orlov, N. K. A1 - Evdokimov, P. V. A1 - Milkin, P. A. A1 - Garshev, A. V. A1 - Putlayev, V. I. A1 - Grebenev, V. V. A1 - Günster, Jens T1 - Phase equilibria in CaNaPO4-CaKPO4 system and their influence on formation of bioceramics based on mixed Ca-K-Na phosphates N2 - An investigation of the two-component phase diagram of the CaNaPO4- CaKPO4system performed using various analysis techniques is reported. The continuous solid solution series of α-CaMPO4 existing above 700 °C undergoes eutectoid decomposition during cooling to β-CaMPO4-based solid solutions enriched with Na and K, and to an intermediate nonstoichiometric compound with an ideal composition of CaK0.6Na0.4PO4. All three compounds exhibit significant volumetric effects associated with first-order phase transitions, with positive volume changes under cooling for the intermediate compound. Increased K content in ceramics based on CaKyNa1-yPO4 compositions enhances the strength properties of those ceramics, including their fracture toughness, which is associated with increased density. Increased K content also has a smaller effect of inducing phase transformations accompanied by strong volume changes. KW - Phase transformations KW - Bioceramics KW - Mixed Ca-K-Na phosphates KW - Na and K rhenanites KW - Phase diagram PY - 2019 DO - https://doi.org/10.1016/j.jeurceramsoc.2019.07.044 VL - 39 IS - 16 SP - 5410 EP - 5422 PB - Elsevier Ltd. AN - OPUS4-49621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orlov, N. K. A1 - Milkin, P. V. A1 - Evdokimov, P. A. A1 - Putlayev, V. I. A1 - Günster, Jens T1 - Sintering of sodium and potassium tcp based ceramic for bone grafting application N2 - Biomaterials for bone replacement and grafting should possess sufficient strength, be bioresorbable and demonstrate osteoconductive and osteoinductive properties. However, resorption of modern materials for bone grafting (hydroxyapatite (HA) and tricalcium phosphate (TCP)) is reported, in some cases, to be not enough, this is why the search for more soluble compounds compared to HA and TCP looks very perspective. A possible way to increase ceramics solubility leads to partial substitution of Ca2+ -ions in Ca3(PO4)2 by alkali cations, like Na+ or/and K+. Improvement of solubility stems from decreasing lattice energy of a substituted phase, as well as the increase in hydration energy of the ions releasing from the phase to ambient solution. From this viewpoint, bioceramics based on compositions from Ca3(PO4)2 - CaKPO4 - CaNaPO4 ternary system seems to be prospective for bone replacement and grafting in the sense of resorption properties. At the same time, one should bear in mind that solubility level (resorbability) is governed not only by reduction of lattice energy but also by microstructure features. Grain sizes and porosity contribute much to dissolution rate making the study of sintering of the ceramics mentioned above highly important. To control Ca3(PO4)2 - CaKPO4 - CaNaPO4 based ceramic microstructure it is necessary to know possible phase transformations in the system and the way to manage microstructure by sintering schedule or sintering process. In this work, an isothermal section for phase diagram of Ca3(PO4)2 - CaKPO4 - CaNaPO4 ternary system is studied with several techniques. According to the XRD of quenched samples, this phase triangle has four single-phase areas at 1200˚C (Figure 1). It was shown that single-phase CaK0.6Na0.4PO4 cannot be sintered to full-dense ceramics by conventional sintering regardless time-temperature schedule. Two-step sintering technique, beneficial in the case of HA-ceramics, was unsuccessful in all cases of calcium-alkali phosphate compositions. However, field-assisted sintering techniques like, e.g. Spark Plasma Sintering (SPS), can overcome this problem due to significant impact on grain boundary diffusion. In connection with this fact, grains grow much slower retaining sintering process in a pore control regime. In this work CaK0.6Na0.4PO4 low-porous ceramics was also fabricated by FAST-methods of sintering. Moreover, other alternative sintering techniques, such as reaction sintering, may be useful in accelerating ions diffusion but stopping excessive grain growth.Strength properties of ceramics were evaluated by B3B-testing, micro- and nanoindentation techniques. Fracture toughness also becomes higher with potassium content increase, guiding porosity level. Resorption properties of sintered ceramics were studied in different solutions with pH=5 and 7.4. Acknowledgements. The research of sintering processes in calcium phosphate materials were funded by RFBR according to the research project № 18-33-00974. T2 - XVI ECerS Conference 2019 CY - Turin, Italy DA - 16.06.2019 KW - Phase transformations KW - Bioceramics KW - Mixed Ca-K-Na phosphates KW - Na and K rhenanites KW - Phase diagram PY - 2019 AN - OPUS4-49622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens A1 - Zocca, Andrea T1 - Dense Powder Beds for the Additive Manufacturing of Ceramics N2 - Many of the most successful and precise additive manufacturing (AM) technologies are based on the deposition layer-by-layer of a flowable powder. Since the first pioneering work at the end of the 1980th many developments have been introduced, greatly extending the use of different materials, improving the physical properties of the components built and enhancing the accuracy of the process. Still very important issues remain nowadays, hampering a completely autonomous production of parts and even restricting the freedom of design by means of these technologies. One of the major issues is the low density and stability of the parts during the building process, which implies the need of support structures: The powder bed surrounding the part has an essential role, since it should support the structure during building, until it’s ready for removal. Moreover, the microstructure of the powder bed is a template for the microstructure of the part produced. In this context, the use of submicron ceramic powders is still a challenge. Three approaches for the stabilization and densification of powder beds will be presented: The Layerwise Slurry Deposition process LSD, the gas flow assisted powder deposition and the Laser Induced Slipcasting (LIS) of ceramic powder compacts. T2 - 43rd International Conference and Exposition on Advanced Ceramics and Composites (ICACC 2019) CY - Daytona Beach, FL, USA DA - 27.01.2019 KW - Ceramics KW - Additive Manufacturing PY - 2019 AN - OPUS4-49627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Powder-based Additive Manufacturing at Micro-Gravity N2 - Are we ready for putting a human footprint on Mars? Obviously, it is possible to send technologically challenging missions to our earth neighbors with a high level of complexity, such as enabling autonomous planetary mobility. As humanity contemplates mounting manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments safely working in space for years. Humans require water and air provided by complicated equipment. Its safe operation is a great challenge and implies being prepared for all eventualities. Instead of foreseeing and preparing for all possible scenarios of machine failures and accidents, it appears logic taking advantage of the flexibility of humans and providing essential equipment for the reaction on critical situations. The supply of spare parts for repair and replacement of lost equipment would be one key pillar of such a strategy. Bearing in mind the absolute distance and flight trajectories for manned missions to Mars, supplying spare parts from Earth is impossible. Thus, in space manufacturing remains the only option for a timely supply. With a high flexibility in design and the ability to manufacture ready to use components directly from a computer aided model, additive manufacturing technologies appear extremely attractive. For metal parts manufacturing the Laser Beam Melting process is the most widely used additive manufacturing process in industrial application. However, envisioning the handling of metal powders in the absence of gravitation is one prerequisite for its successful application in space. A gas flow throughout the powder bed has been successfully applied to compensate for missing gravitational forces in micro gravity experiments. The so-called Gas Flow Assisted Powder Deposition is based on a porous building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. T2 - 1st Sino-German Workshop on 3D Printing in Space CY - Beijing, China DA - 20.02.2019 KW - Zero-g KW - Additive Manufacturing KW - µ-gravity PY - 2019 AN - OPUS4-49628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Powder-based Additive Manufacturing at Micro-Gravity N2 - Are we ready for putting a human footprint on Mars? Obviously, it is possible to send technologically challenging missions to our earth neighbors with a high level of complexity, such as enabling autonomous planetary mobility. As humanity contemplates mounting manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments safely working in space for years. Humans require water and air provided by complicated equipment. Its safe operation is a great challenge and implies being prepared for all eventualities. Instead of foreseeing and preparing for all possible scenarios of machine failures and accidents, it appears logic taking advantage of the flexibility of humans and providing essential equipment for the reaction on critical situations. The supply of spare parts for repair and replacement of lost equipment would be one key pillar of such a strategy. Bearing in mind the absolute distance and flight trajectories for manned missions to Mars, supplying spare parts from Earth is impossible. Thus, in space manufacturing remains the only option for a timely supply. With a high flexibility in design and the ability to manufacture ready to use components directly from a computer aided model, additive manufacturing technologies appear extremely attractive. For metal parts manufacturing the Laser Beam Melting process is the most widely used additive manufacturing process in industrial application. However, envisioning the handling of metal powders in the absence of gravitation is one prerequisite for its successful application in space. A gas flow throughout the powder bed has been successfully applied to compensate for missing gravitational forces in micro gravity experiments. The so-called Gas Flow Assisted Powder Deposition is based on a porous building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. T2 - 2nd Sino-German Workshop on 3D Printing in Space CY - Berlin, Germany DA - 28.10.2019 KW - µ-gravity KW - Additive Manufacturing KW - Zero-g PY - 2019 AN - OPUS4-49629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten T1 - Alternative Verfahren zur Strukturierung von Grünfolien und Laminaten N2 - Die Strukturierung keramischer Grünfolien und Laminate ist ein wesentlicher Prozessschritt in der keramischen Multilayer-Technologie und begründet die funktionelle Vielfalt keramischer Multilayer. Benötigt wird die Grünbearbeitung für die Herstellung elektrischer und thermischer Vias sowie innerer Kavitäten und Kanäle für Transport und Lagerung von Gasen und Flüssigkeiten in hochintegrierten Schaltungsträgern, Sensoren und Reaktoren. Standardverfahren in der industriellen Fertigung sind Heißschneiden, Stanzen und Laserbearbeitung. Darüber hinaus werden auch Bohren, Fräsen, Sägen und Heißprägen verwendet. Über die Erprobung weiterer Verfahren wie Wasserstrahlschneiden, Dampfstrahlätzen und Powder Blasting wird in der Literatur berichtet. Im Vortrag werden spezifische Vor- und Nachteile der eingesetzten Verfahren beleuchtet. Abschließend werden die Kriterien für die Auswahl des optimalen Strukturierungsverfahrens diskutiert. Zusammensetzung und Gefüge sowie die dadurch bedingten mechanischen und thermomechanischen Eigenschaften sowie das Absorptionsverhalten von Grünfolien sind sehr unterschiedlich. Daraus resultieren unterschiedliche optimale Bearbeitbarkeitsparameter. T2 - DKG-Seminar "Foliengieß- und Schlitzdüsenverfahen" CY - Hermsdorf, Germany DA - 05.11.2019 KW - Stanzen KW - Keramische Folien KW - Laserbearbeitung KW - Grünfolieneigenschaften PY - 2019 AN - OPUS4-49742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Kraus, David A1 - Kübler, Stefan A1 - Eisermann, René T1 - Multiaxial fatigue damage of glass fiber reinforced polymers N2 - Fiber reinforced polymers (FRPs) are a well established material in lightweight applications, e.g. in automotive, aerospace or wind energy. The FRP components are subjected to multiaxial mechanical as well as hygrothermal loads. Common operation temperatures are in the range of 213 K and 373 K (-60 °C and 100 °C) at a relative humidity of 10% to 90%. In spacecraft applications, the environmental conditions are even more extreme. However, the correlation between multiaxial mechanical loading and harsh environment conditions have to-date not been investigated in detail. The project aims to investigate the fatigue behavior of FRPs dependent on multiaxial mechanical loading, temperature, and humidity. Extensive experimental testing is performed on flat plate and cylindrical tube specimens, accompanied by numerical and analytical calculations. T2 - 24. Nationales SAMPE Symposium CY - Dresden, Germany DA - 06.02.2019 KW - Composite KW - Fatigue KW - Thermomechanics KW - Distributed fiber optic sensors PY - 2019 AN - OPUS4-47335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Erdmann, Maren A1 - Böhning, Martin A1 - Niebergall, Ute T1 - Physical and chemical effects of biodiesel storage on high-density polyethylene: Evidence of co-oxidation N2 - The physical and chemical effects of diesel and biodiesel fuels on two high-density polyethylene (PE-HD) types were investigated. Both semi-crystalline PE-HD are common thermoplastic materials for container and storage tank applications. Biodiesel, a composition of unsaturated fatty acid esters from renewable resources, was chosen as it is regarded a possible green alternative to fossil fuels. The study aims at identifying significant differences between biodiesel and conventional diesel fuels based on the differences in the chemical nature of the two. The physical effects of the fuels on the polymer at first comprises the sorption behavior, i.e. kinetics and final equilibrium concentration. Not only are both fuels absorbed by the amorphous phase of the semi-crystalline PE-HD, they also induce a plasticization effect that modifies the molecular mobility and therefore also the characteristic yielding properties, manifest in the obtained stress-strain curves. The chemical effects related to degradation phenomena is investigated by a long-term storage scenario using partially immersed tensile test specimens in diesel and biodiesel. We were able to confirm the proposed co-oxidation mechanism by Richaud et al. for polyethylene-unsaturated penetrant systems on a larger scale based on practical tensile tests. One of the investigated polyethylene grades subjected to tensile drawing showed a significant loss of plastic deformation and the onset of premature failure after 150 days of storage in biodiesel. Further biodiesel storage showed a systematically reduced elongation at break before necking. None of these effects were observed in diesel. Oxidation of fuels and polymer after progressing storage times were analyzed by the evolution of carbonyl species in FT-IR/ATR spectroscopy. KW - Biodiesel KW - Degradation KW - Long-term storage KW - Sorption KW - Diesel PY - 2019 DO - https://doi.org/10.1016/j.polymdegradstab.2019.01.018 SN - 0141-3910 VL - 161 IS - 1 SP - 139 EP - 149 PB - Elsevier CY - Amsterdam AN - OPUS4-47268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenberg, Rainer T1 - Modelling of environmentally assisted material degradation in the crack phase-field framework N2 - The simulation of crack propagation was conducted with a diffusive crack model in a variational framework. Moreover, the physically sound introduction of mass transport and coupling mechanisms due to environmentally assisted effects could be realised in this framework. The objective consists of the application of the phase-field Approach towards the simulation of environmentally assisted material degradation with the advantage of a non-required predefined crack path and a mesh-independent non-local formulation that facilitates the damage evolution with respect to material softening. The sharp crack is regularised by the introduction of a phase-field order parameter leading to a diffusive crack formulation. Besides the equations originating from the linear momentum balance an additional evolution equation for the crack phase-field is introduced. Furthermore, mass transport is simulated by a Diffusion equation. The description delivered by the variational phase-field framework is able to simulate crack propagation according to published numerical test cases. Additionally, the calculation of stress intensity factors is possible as well as crack resistance curves that describe stable crack propagation. KW - Fracture mechanics KW - Crack propagation KW - Phase-field KW - Mass transport KW - Environmentally assisted cracking PY - 2019 DO - https://doi.org/10.1177/1464420718761220 SN - 1464-4207 VL - 233 IS - 1 SP - 5 EP - 12 PB - SAGE AN - OPUS4-47152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kraus, David T1 - Einfluss thermischer Lasten auf die Schädigung von Faser-Kunststoff-Verbunden N2 - Faser-Kunststoff-Verbunde (FKV) werden zunehmend in der Luft- und Raumfahrt, der Automobil- und Windenergieindustrie eingesetzt. Die hier entwickelten Bauteile sind oft nicht nur multiaxialen mechanischen Belastungen, sondern auch hohen klimatischen Beanspruchungen ausgesetzt. Einsatztemperaturen zwischen -60°C und 100°C bei 10-90% relativer Feuchte sind keine Seltenheit, in der Raumfahrt sind die thermischen Belastungen noch extremer. Die Auswirkungen einer Wechselwirkung extremer klimatischer Beanspruchungen mit multiaxialen mechanischen Belastungen wurden bisher kaum betrachtet. Das Ziel des Projektes ist die Untersuchung des Ermüdungsverhaltens der Faser-Kunststoff-Verbunde in Abhängigkeit von multiaxialer mechanischer Belastung, Temperatur und Feuchte. Dazu werden umfangreiche experimentelle Untersuchungen an Flach- und Rohrproben sowie numerische und analytische Berechnungen durchgeführt. Im Rahmen des Seminarvortrags wird eine mikromechanische Modellierung der thermischen Eigenspannungen innerhalb des FKV vorgestellt, welche anhand eines Finite-Elemente-Modells validiert wird. Zur Bestimmung einer Schädigungsgrenze werden verschiedene Energieansätze diskutiert, welche anschließend mit den experimentell erhaltenen Ergebnissen im Temperaturbereich zwischen -60 °C und 70 °C verglichen werden. Dabei wird gezeigt, dass mithilfe der mikromechanischen Formulierung eine temperaturunabhängige Masterschädigungslinie für quasistatisch belastete Probekörper abgeleitet werden kann. Des Weiteren können Elastizitäten und Festigkeiten in Abhängigkeit der Temperatur mit den mikromechanischen Mischungsregeln bestimmt werden. So kann der experimentelle Aufwand beim Nachweis thermomechanisch belasteter Strukturen reduziert werden. Ein ähnlicher Ansatz wird für schwingende Ermüdungsbelastung bei verschiedenen Umgebungstemperaturen diskutiert und experimentell überprüft. T2 - Kolloquium Luftfahrzeugbau und Leichtbau, TU Berlin CY - Berlin, Germany DA - 18.02.2019 KW - Composite KW - Ermüdung KW - Faser-Kunststoff-Verbunde KW - Thermomechanik KW - Schädigung PY - 2019 AN - OPUS4-47405 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Low Cycle Fatigue and Relaxation Performance of Ferritic–Martensitic Grade P92 Steel N2 - Due to their excellent creep resistance and good oxidation resistance, 9–12% Cr ferritic–martensitic stainless steels are widely used as high temperature construction materials in power plants. However, the mutual combination of different loadings (e.g., creep and fatigue), due to a “flexible” operation of power plants, may seriously reduce the lifetimes of the respective components. In the present study, low cycle fatigue (LCF) and relaxation fatigue (RF) tests performed on grade P92 helped to understand the behavior of ferritic–martensitic steels under a combined loading. The softening and lifetime behavior strongly depend on the temperature and total strain range. Especially at small strain amplitudes, the lifetime is seriously reduced when adding a hold time which indicates the importance of considering technically relevant small strains. KW - Ferritic–martensitic steel KW - P92 KW - Low cycle fatigue KW - Relaxation fatigue KW - Cyclic softening PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473905 DO - https://doi.org/10.3390/met9010099 VL - 9 IS - 1 SP - 99, 1 EP - 25 PB - MDPI AN - OPUS4-47390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüchtenborg, Jörg A1 - Kober, D. A1 - Weber, A. P. A1 - Melcher, J. A1 - Günster, Jens T1 - Textured dense zinc oxide layers for active noise canceling windows N2 - Dense ZnO films with a strong c‐axis texture have been deposited on transparent conductive oxide glass, glass, and Si wafers, respectively, with a two‐step pressureless wet chemical method using zinc acetate dihydrate as Zn‐precursor. The crystallographic structure of the films has been studied with XRD and scanning electron microscopy. Optical measurements reveal a high transparency of the ZnO films with a thickness of up to 10 μm. This new cost‐effective route for ZnO film deposition does not require expensive sophisticated equipment and is easily upscaled. KW - ZnO PY - 2019 DO - https://doi.org/10.1111/jace.15928 SN - 0002-7820 VL - 102 IS - 3 SP - 988 EP - 996 PB - Wiley AN - OPUS4-47519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tielemann, Christopher A1 - Reinsch, Stefan A1 - Patzig, C. A1 - Höche, T. A1 - Busch, R. T1 - Surface Initiated Microstructure Formation in Glass -Ceramics N2 - Übersicht zur Oberflächeninitiierten Mikrostrukturbildung in Glasoberflächen. Dabei wird auf die Kristallvorzugsorientierung senkrecht zur Oberfläche der sich unter Temperatureinfluss behandelten Glasproben eingegangen. Zudem werden die ersten Experimente zur Eingrenzung des Ursprungs dieser Orientierung vorgestellt. N2 - Overview about the surface initiated microstructure formation in glass surfaces. Samples which are exposed to a temperature treatment, can develop a crystalline microstructure above Tg at the surface. These separated crystals can be preferably oriented towards the surface of the sample. First experiments about the origin of these orientation phenomenon as well as the potentially causing mechanisms are presented and discussed within the presentation. T2 - AK Glasig-kristalline Multifunktionswerkstoffe 2019 CY - TU Clausthal, Germany DA - 21.02.2019 KW - Orientation KW - Glass KW - Crystallization KW - Diopside PY - 2019 AN - OPUS4-47537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh A1 - Trappe, Volker T1 - Restoring structural integrity - localized repairs for wind turbine rotor blades N2 - The effect of localized repairs on the mechanical properties and thus the lifespan of wind turbine rotor blade shells is examined. T2 - SAMPE Symposium 2019 CY - Dresden, Germany DA - 06.02.2019 KW - Fatigue KW - Glass fiber reinforced polymers KW - Lightweight materials KW - Sandwich KW - Wind turbine blades PY - 2019 AN - OPUS4-47443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Hornbogen, E. A1 - Warlimont, H. A1 - Skrotzki, Birgit T1 - Metalle N2 - Dieses Standardwerk bietet eine Darstellung der Struktur und Eigenschaften der Metalle und ihrer Anwendungen als Werkstoffe. Im ersten, wissenschaftlichen Teil werden der atomare und mikroskopische Aufbau, die thermodynamischen und die grundlegenden physikalischen und mechanischen Eigenschaften der Metalle beschrieben sowie die Grundlagen der thermisch aktivierten Reaktionen und der Phasenumwandlungen. Die wichtigsten experimentellen Untersuchungsmethoden werden erläutert, wobei die mikroskopischen und Beugungsverfahren einen Schwerpunkt bilden. Im zweiten, technischen Teil werden die Werkstoffgruppen der Metalle und ihre anwendungsbezogenen Eigenschaften behandelt. Dabei wird auf die zugrunde liegenden Legierungen und die Verfahren zur gezielten Einstellung ihrer Eigenschaften eingegangen. Schwerpunkte bei der Darstellung der Werkstoffe sind die Stähle, die teilchengehärteten Legierungen, die Magnetwerkstoffe und die pulvermetallurgisch hergestellten Werkstoffe. Außerdem werden die Oberflächeneigenschaften und die Verfahren zur Oberflächenbehandlung dargestellt. KW - Struktur KW - Eigenschaften KW - Anwendungen PY - 2019 SN - 978-3-662-57762-2 DO - https://doi.org/10.1007/978-3-662-57763-9 SP - 1 EP - 424 PB - Springer Vieweg CY - Berlin ET - 7. AN - OPUS4-47549 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Marquardt, J. A1 - Gurieva, G. A1 - Stephan-Scherb, Christiane A1 - Schorr, S. T1 - The Effect of Copper Vacancies on the Anion Position of Chalcopyrite Type CuGaS2 N2 - The prediction of structural parameters and optoelectronic properties of compound semiconductors is very important. However, calculations often neglect chemical variability and structural defects. In chalcopyrite type semiconductors one of the major defects are copper vacancies (V Cu). The four cation neighbors of the anion determine its position in the chalcopyrite type structure expressed by the Wyckoff position 8d (x, 1/4, 1/8). Intrinsic point defects like V Cu and anti-sites may cause variations of the Anion position in the middle of the cation tetrahedron, especially in the Anion position Parameter x. For stoichiometric chalcopyrite type compounds a formalism according to the principle of conservation of tetrahedral bonds (CTB) can be applied to calculate the anion position parameter, but it fails in the case of off-stoichiometric chalcopyrites. This case study of chalcopyrite type CuGaS 2 and Mn-substituted GuGaS 2 shows that the experimentally determined anion position Parameter x deviate from values calculated by CTB approach. The systematic investigation of off-stoichiometric CuGaS 2 and Mn-substituted GuGaS 2 demonstrates the effect of copper vacancies on the average radii of the cation sites (Wyckoff positions 4a and 4b) as well as on the anion position Parameter x. By applying an elaborated CTB Approach implementing copper vacancies an agreement between experimental and calculated anion position Parameter x can be obtained. KW - Chalcogenides KW - Neutron diffraction KW - Copper vacancies PY - 2019 DO - https://doi.org/10.1002/pssa.201800882 VL - 216 IS - 15 SP - 1800882 PB - Wiley AN - OPUS4-47748 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Babutzka, Martin A1 - Trappe, Volker A1 - Pittner, Andreas A1 - Krankenhagen, Rainer A1 - Kühne, Hans-Carsten T1 - Vorstellung des Aktivitätsfelds Erneuerbare Energie N2 - Auf der Beiratssitzung des TF Energie wurde das Aktivitätsfeld Erneuerbare Energien in seinem breiten Spektrum (aber selektive Auswahl) vorgestellt. T2 - Beiratssitzung TF Energie CY - BAM Berlin-Adlershof, Germany DA - 09.04.2019 KW - Erneuerbare Energien KW - Windenergie PY - 2019 AN - OPUS4-47751 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea A1 - Lüchtenborg, Jörg A1 - Günster, Jens A1 - Diener, S. A1 - Lima, P. A1 - Katsikis, N. T1 - Layerwise Slurry Deposition for the Additive Manufacturing of Ceramics N2 - In powder bed Additive Manufacturing (AM) technologies, a part is produced by depositing and piling up thin powder layers. In each layer, the cross section of the object to build is defined by locally consolidating the powder, by sintering/melting the material (powder bed fusion technologies) or by ink jetting a binder (binder jetting technologies). These are already leading AM technologies for metals and polymers, thanks to their high productivity and scalability. The application of these techniques to most ceramics has been challenging so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer. The LSD offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and enables the production of parts with physical and mechanical properties comparable to pressed or slip-casted parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported. T2 - ICACC 2019 - 43rd International Conference and Exposition on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 27.01.2019 KW - Additive Manufacturing KW - Ceramic KW - Layerwise KW - Slurry PY - 2019 AN - OPUS4-47865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea A1 - Lima, P. A1 - Lüchtenborg, Jörg A1 - Mühler, T. A1 - Günster, Jens T1 - Advanced ceramics by powder bed 3D printing N2 - Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. However, the flowability of the powder used in these processes is essential to achieve defect-free and densely packed powder layers. For standard powder bed AM technologies, this limits the use of many raw materials which are too fine or too cohesive. This presentation will discuss the possibilities to either optimize the powder raw material to adapt it to the specific AM process, or to develop novel AM technologies which are able to process powders in a wider range of conditions. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of very fine ceramic particles. Another technology, the Gas Flow Assisted Powder Deposition, can increase the stability of the powder bed and the packing density, even in extreme conditions such as in absence of gravitational forces. T2 - yCAM 2019 - young Ceramists Additive Manufacturing Forum CY - Mons, Belgium DA - 03.04.2019 KW - Additive Manufacturing KW - Flowability KW - Ceramic KW - Powder PY - 2019 AN - OPUS4-47867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea A1 - Lüchtenborg, Jörg A1 - Lima, P. A1 - Günster, Jens T1 - Additive Manufacturing of Ceramic Materials N2 - Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer, which can be used for SLM or for 3DP. This technique offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and is capable of producing parts with physical and mechanical properties comparable to traditionally shaped parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported. T2 - First Sino-German Workshop on 3D Printing in Space CY - Beijin, China DA - 20.02.2019 KW - Additive Manufacturing KW - Ceramic KW - Layerwise PY - 2019 AN - OPUS4-47868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan T1 - Considerations for nanomaterial identification of powders using volume-specific surface area method N2 - The EC’s recommendation for a definition of nanomaterial (2011/696/EU) should allow the identification of a particulate nanomaterial based on the number-based metric criterion according to which at least 50% of the constituent particles have the smallest dimension between 1 and 100 nm. However, it has been recently demonstrated that the implementation of this definition for regulatory purposes is conditioned by the large deviations between the results obtained by different sizing methods or due to practical reasons such as high costs and time-consuming. For most measurement methods for particle size determination it is necessary to initially disperse the particles in a suitable liquid. However, as the particle size decreases, the adhesion forces increase strongly, making it more difficult to deagglomerate the particles and to assess accurately the result of this process. Therefore, the success of the deagglomeration process substantially determines the measurement uncertainty and hence, the comparability between different methods. Many common methods such as dynamic light scattering (DLS), centrifugal liquid sedimentation (CLS) or ultrasound attenuation spectroscopy (US) can give good comparable results for the size of nanoparticles, if they are properly separated and stabilized (e.g. in reference suspensions). In order to avoid the use of hardly available and expensive methods such as SEM / TEM for all powders, an agglomeration-tolerant screening method is useful. One of the measurement methods well suited to probe the size of particulate powder is the determination of the volume-specific surface area (VSSA) by means of gas adsorption as well as skeletal density. The value of 60 m2/cm3 corresponding to spherical, monodisperse particles with a diameter of 100 nm constitutes the threshold for decisioning if the material is a nano- or non-nanomaterial. The identification of a nanomaterial by VSSA method is accepted by the EU recommendation. However, the application of the VSSA method was associated also with some limitations. The threshold of 60 m2/cm3 is dependent on the particle shape, so that it changes considerably with the number of nano-dimensions, but also with the degree of sphericity of the particles. For particles containing micro-pores or having a microporous coating, false positive results are induced. Furthermore, broad particle size distributions made necessary to additionally correct the threshold. Based on examples of commercially available ceramic powders, the applicability of the VSSA approach was tested in relation with SEM and TEM measurements. The introduction of a correction term for deviations from sphericity and further additions improved the applicability of VSSA as a screening method. T2 - Partec CY - Nuremberg, Germany DA - 09.04.2019 KW - VSSA KW - Nanoparticles PY - 2019 AN - OPUS4-47874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Bettge, Dirk A1 - Kratzig, Andreas A1 - Knauer, S. T1 - Factors Influencing Droplet Corrosion in Dense Phase CO2 N2 - Recent studies have shown that even at a very low concentration of impurities (less than 100 ppmv of SO2, NO2, O2 and H2O) the droplet formation and condensation of sulfuric and nitric acids in dense phase CO2 are possible and observable. To reveal the mechanism of droplet corrosion in dense phase CO2 at high pressure and low temperature, further studies on factors that affect wettability and resulting corrosion behaviors of transport pipeline steels are needed. In this study, effects of surface morphology were investigated by varying surface roughness of carbon steel coupons exposed to CO2 stream containing impurities to measure the wettability by contact angle and to observe the condensation as well as possible droplet corrosion that followed. Other considered factors were: pH of the droplet, temperature, droplet volume, and exposure time. T2 - NACE International Corrosion Conference 2019 CY - Nashville, TN, USA DA - 24.03.2019 KW - CCUS KW - Dense phase KW - CO2 KW - Droplet KW - Corrosion KW - Condensation KW - Carbon steel PY - 2019 SP - 13017-1 EP - 13017-13 PB - NACE International CY - Houston AN - OPUS4-47915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk ED - Petzow, G. T1 - In-situ Messung der 3D-Topografie von Bruchflächen im REM N2 - Die Abbildung von Bruchflächen im Rasterelektronenmikroskop (REM) liefert hochaufgelöste Bilddaten, die für die mikrofraktografische Bewertung von Bruchmechanismen unerlässlich sind. Die Ermittlung von Bruchmechanismen ist oft ein wichtiger Teil von Schadensanalysen zur Ermittlung der Bruchursache. Durch den Abbildungsprozess im REM gehen räumliche Informationen im Normalfall größtenteils verloren und können daher nicht zur Präzisierung des Bruchmechanismus herangezogen werden. Um räumliche Informationen von Probenoberflächen im REM zu erfassen, gibt es verschiedene Methoden. Die für die Ermittlung der 3D-Topografie bereits länger eingeführten Verfahren mittels Proben- oder Strahlkippung können die Berechnung des Oberflächenmodells erst nach der seriellen Aufnahme mehrerer Bilder vornehmen. Mit der Verwendung eines segmentierten Rückstreudetektors ist dagegen die Erzeugung eines 3D-Oberflächenmodells während der Bildaufnahme praktisch in Echtzeit möglich. Die Probentopografie wird gleichzeitig mit dem Bildeinzug dargestellt und gespeichert. T2 - Metallographietagung 2019 CY - Dresden, Germany DA - 18.09.2019 KW - Fraktografie KW - Schadensanalyse KW - Topografie KW - 3D KW - REM PY - 2019 SN - 978-3-88355-417-4 VL - 2019/53 SP - 175 EP - 180 PB - DGM AN - OPUS4-49332 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sommer, Konstantin A1 - Ávila, Luis T1 - Microstructure ageing of stainless steel AISI 316L manufactured by selective laser melting (SLM) N2 - Additive manufacturing (AM) processes, such as SLM, offer a variety of advantages compared to conventional manufacturing. Today AM parts are still comparatively less cost-effective if they are manufactured in large quantities. To make the AM parts more cost-efficient, the AM process has to be improved. It requires a good understanding of microstructure formation, microstructure-property-relations and ageing processes affected by different loads. In this work the ageing behavior of SLM manufactured AISI 316L stainless steel is evaluated. The microstructure effected by mechanical, thermal and corrosive loads are investigated and compared to as-built microstructure. Tensile tests are used for mechanical ageing. For thermal and corrosive loads the typical application conditions of 316L apply. The methods of microstructure investigation include SEM, TEM, CT and EBSD. The main object of this work is the description of microstructure and ageing processes of AM parts. T2 - European Conference on Structural Integrity of Additively Manufactured Materials (ESIAM) 2019 CY - Trondheim, Norway DA - 09.09.2019 KW - 316L KW - Selective laser melting KW - Microstructure evolution PY - 2019 AN - OPUS4-49886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schulz, Wencke A1 - Stephan-Scherb, Christiane A1 - Laplanche, Guillaume T1 - High temperature oxidation behavior of CrMnFeCoNi and CrCoNi in various atmospheres N2 - The study presented here focusses on a systematic analysis of oxidation mechanisms of the well-known Cr20Mn20Fe20Co20Ni20 alloy and one of its ternary sub-system Cr33.3Co33.3Ni33.3 which were reported in the literature to exhibit attractive mechanical properties. Both alloys are single phase fcc prior to oxidation and were simultaneously exposed to different oxygen containing atmospheres at 700° C and 800° C for durations up to 288 h. Cr20Mn20Fe20Co20Ni20 showed poor oxidation resistance at high temperatures due to its high amount of manganese leading to the formation of non-protective Mn-oxide scales. In contrast, a relatively homogeneous and protective chromia layer was found to form on CrCoNi at 700° C and 800° C after each exposure time. Mass change-, SEM- and XRD analysis of the oxide layers were performed in the present study and provide a better understanding of the oxidation mechanisms as well as the impact of the alloy composition on oxidation behavior. T2 - World Congress on High Entropy Alloys (HEA 2019) CY - Seattle, WA, USA DA - 17.11.2019 KW - Scanning electron microscopy KW - High-entropy alloys KW - High-temperature corrosion PY - 2019 AN - OPUS4-50309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Elucidation of Surface Degradation Phenomena By In Situ X-ray techniques N2 - Presentation of in situ and real time approaches to study high temperature oxidation phenomena by adavnced X-ray techniques. Application to the analysis of degradation mechanisms of chemical complex alloys and high entropy alloys was presented. T2 - SPP 2006 Hot Topic Meeting "Large Scale Facility Based Techniques CY - Helmholtz-Zentrum Berlin für Materialien und Energie, Germany DA - 26.09.2019 KW - High entropy alloys KW - Diffraction KW - In situ KW - Oxidation PY - 2019 AN - OPUS4-49134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Schiller, B.N A1 - Beck, M. A1 - Bettge, Dirk T1 - On the corrosion behaviour of CO2 injection pipe steels: Role of cement N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost-effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells, the corrosion resistance of the materials used needs to be determined. In this study, representative low-cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were investigated in simulated pore water at 333 K and under CO2 saturation condition to represent the worst-case scenario: CO2 diffusion and aquifer fluid penetration. These simulated pore waters were made from relevant cement powder to mimic the realistic casing-cement interface. Electrochemical studies were carried out using the pore water made of cement powder dissolved in water in comparison with those dissolved in synthetic aquifer fluid, to reveal the effect of cement as well as formation water on the steel performance. Two commercially available types of cement were investigated: Dyckerhoff Variodur® and Wollastonite. Variodur® is a cement containing high performance binder with ultra-fine blast furnace slag which can be used to produce high acid resistance concrete. On the other hand, Wollastonite is an emerging natural material mainly made of CaSiO3 which can be hardened by converting to CaCO3 during CO2 injection. The results showed the pH-reducing effect of CO2 on the simulated pore water/aquifer (from more than 10 to less than 5) leading to the active corrosion process that happened on both 1.8977 and 1.7225. Electrochemical characterization showed negative free corrosion potential and polarisation curves without passive behaviors. The tested coupons suffered from pitting corrosion, which was confirmed by surface analysis. Interestingly, basing on the pit depth measurements from the tested coupons and the hardness of cement powder, it is suggested that Variodur® performed better than Wollastonite in both aspects. The electrochemical data was compared to that resulted from exposure tests to give a recommendation on material selection for bore-hole construction. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Carbon capture KW - Utilization, and storage (CCUS) technology KW - Corrosion KW - Carbon steel KW - Mortel KW - Crevice corrosion PY - 2019 AN - OPUS4-49105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falk, Florian A1 - Stephan-Scherb, Christiane A1 - Lehmusto, J. A1 - Pint, B. T1 - The impact of water vapour on high-temperature surface degradation by sulfurous gases of ferritic alloys N2 - Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This work investigates the effect of water vapor in the initial stages of SO2 corrosion of an ferritic model alloy containing 9 wt% Cr and 0.5 wt% Mn. The exposure experiments were studied at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale–alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere. T2 - EUROCORR CY - Barceló Sevilla Renacimiento, Seville, Spain DA - 09.09.2019 KW - Diffraction KW - Sulfidation KW - Early oxidation KW - Corrosion KW - In situ PY - 2019 AN - OPUS4-49213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. A1 - Agudo Jácome, Leonardo T1 - Thermodynamic study of a refractory complex concentrated alloy using the CALPHAD method N2 - Introduction/purpose: Multi-principal-element alloys (MPEAs), also known as complex concentrated alloys (CCAs), have recently come to the attention of the scientific community due to some interesting and unexpected microstructures, and their potential for improving properties such as, e.g. mechanical strength and oxidation resistance in high temperature structural applications. The AlMo0.5NbTa0.5TiZr refractory (r)CCA is one such candidate, showing a two-phase microstructure after a two-stage heat treatment under argon atmosphere at a controlled cooling rate. Since the application conditions intended for this alloy require a long-term high temperature (> 700 °C) mechanical and oxidation resistance, it becomes necessary to assess the possible phase development in this regime. Methods: In this contribution, the CALPHAD method is used to calculate phase equilibria for the AlMo0.5NbTa0.5TiZr CCA in the presence and absence of oxygen. Equilibrium phase amount evolution with temperature and Scheil Model for solidification (e.g. Fig.1a and Fig.1b, respectively) are analyzed, which are obtained using the databases TCNI9 and TTNI7 and the Gibbs energy minimizer in the Thermo-Calc software. Results: The diagrams reveal that two BCC-based phases could form during alloy solidification, where one phase would be enriched with Mo, Nb and Ta while the other phase, with Al, Ti and Zr. Activity oxides diagrams show that a stable form of aluminum oxide (α-Al2O3, Pearson symbol: hR10, corundum) can be formed. Results obtained by both databases, as well as discrepancies between property phase and Scheil approaches are discussed on the base of experimental results. Conclusions: A modeling tool is used to support alloy characterization and development, providing also the possibility to feedback information to improve existing thermodynamic databases. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - CALPHAD databases analysis KW - Thermodynamic analysis KW - Complex concentrated alloy (CCA) PY - 2019 AN - OPUS4-49345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk T1 - In-situ Messung der 3D-Topografie von Bruchflächen im REM N2 - Die Abbildung von Bruchflächen im REM liefert hochaufgelöste Bilddaten, die für die mikrofraktografische Bewertung von Bruchmechanismen unerlässlich sind. Durch den Abbildungsprozess im REM gehen räumliche Informationen im Normalfall größtenteils verloren. Mit der Verwendung eines segmentierten Rückstreudetektors ist dagegen die Erzeugung eines 3D-Oberflächenmodells während der Bildaufnahme praktisch in Echtzeit möglich. Die hier beschriebene Untersuchung soll die Anwendbarkeit des Verfahrens auf Bruchflächen zeigen. Zukünftig können Topografiedaten dazu beitragen, Bruchflächen besser zu interpretieren. T2 - Metallographietagung 2019 CY - Dresden, Germany DA - 18.09.2019 KW - Fraktografie KW - Schadensanalyse KW - Topografie KW - 3D PY - 2019 AN - OPUS4-49330 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falk, Florian A1 - Stephan-Scherb, Christiane T1 - Microstructural impact on high temperature oxidation behavior of Fe-Cr-C model alloys N2 - Chromia forming high alloyed ferritic-austenitic steels are being used as boiler tube materials in biomass and coal-biomass co-fired power plants. Despite thermodynamic and kinetic boundary conditions, microstructural features such as grain orientation, grain sizes or surface deformation contribute to the oxidation resistance and formation of protective chromium-rich oxide layers. This study elucidates the impact of microstructure such as the grain size and number of carbide precipitates on high temperature oxidation at 650°C in 0.5% SO2 atmosphere. Cold-rolled Fe-16Cr-0.2C material was heat-treated to obtain two additional microstructures. After exposure to hot and reactive gases for 10 h < t < 1000 h layer thicknesses and microstructure of oxide scales are observed by scanning electron microscopy and Energy-dispersive X-ray spectroscopy. The two heat treated alloys showed reasonable oxidation resistance after 1000 h of exposure. The oxidation rate was substantially higher for the alloy with a duplex matrix after heat treatment compared to the fine-grained material. T2 - Gordon Research Conference CY - New London, New Hampshire, USA DA - 21.07.2019 KW - Corrosion KW - Microstructure KW - Oxidation KW - Sulfidation PY - 2019 AN - OPUS4-49212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütter, H. A1 - Le, Quynh Hoa A1 - Knauer, S. A1 - Bettge, Dirk A1 - Kranzmann, Axel T1 - Combining CO2 streams from different emitters ‐ a challenge for pipeline transportation N2 - Depending on the CO2 generating and the capture process as well as on consecutive purification steps applied, CO2 streams from different emitters may differ in their composition. When CO2 streams with different compositions are fed into a larger pipeline network, there are several aspects that must be considered: i) chemical reactions, such as acid formation, may occur within the joint CO2 stream; ii) there may be a variation of mass flow rate and CO2 stream composition within the pipeline network if the feed-in behavior of different CO2 sources changes with time. Potential impacts of changing CO2 stream compositions and mass flow rates in CCS cluster systems were investigated in the collaborative project "CLUSTER" (see also www.bgr.bund.de/CLUSTER). In this presentation, we focus on the experimental investigations of formation and condensation of strong acids and their impacts on the corrosion of pipeline steels. When SO2, NO2, O2 and H2O are present simultaneously in CO2 streams chemical cross-reactions may occur leading to the formation of strong acids such as sulfuric and nitric acid. To prevent this acid formation the concentration of at least one of these four impurities must be kept very low (e.g., Rütters et al., 2016). At temperatures below the acid dew point temperature, acids will condense, e.g., on pipeline steel surfaces. In turn, these acid condensates may trigger steel corrosion. To better understand the process of acid formation and condensation and its implications for steel corrosion, exposure tests were performed on pipeline steel X70 in dense CO2 with varying SO2, NO2 and O2 concentration under high pressure and at 278 K in an observable autoclave, in which water was added as droplets or as vapor. Further, electrochemical tests were carried out with X70 specimens immersed in 500 mL CO2-saturated synthetic condensate solution or in droplets of the same solution on the specimen’s surface. Depending on impurity concentrations in the CO2 streams, condensates consisting of different relative amounts of nitric and sulfuric acid were formed. In condensates containing both nitric and sulfuric acid, corrosion rates were higher than the sum of those of the individual acids. In addition, corrosion products and forms depended on the condensate composition. Investigations of water droplets on steel surfaces in impurity-containing dense-phase CO2 revealed the diffusion of SO2 and NO2, followed by cross-reactions forming corresponding acids. An increase in droplet size (from 1 to 5 µl) lead to higher corrosion rates. However, in comparison to measurements in bulk solution, corrosion reactions in droplets resulted in thick, high-resistance corrosion products and observed droplet corrosion rates were significantly lower. In addition, the possibility of acid droplet formation and growth in impure liquid CO2 is influenced by the wetting behavior of the acid droplet on the steel surface. Thus, the contact angle between a water droplet and the surface steel specimens in a CO2 atmosphere was investigated in a high pressure view cell following the sessile drop method. The contact angle wasand found to be larger at higher CO2 pressures (studied from 5 to 20 MPa) and at higher temperatures (e.g. 278 K to 333 K). Further, measured contact angles were larger on rough than on smooth metal surfaces. In addition, acid formation reduced the contact angle, i.e. lead to better wetting, thereby stimulating condensation that was followed by a corrosion process. These detailed insights on the complex interplay of acid formation, condensation, wetting behavior and corrosion allow a better assessment of material suitability for pipeline transportation of impure CO2 streams T2 - TCCS-10 The 10th Trondheim Conference on Carbon Capture, Transport and Storage CY - Trondheim, Norway DA - 17.06.2019 KW - arbon capture KW - utilization, and storage (CCUS) technology KW - corrosion KW - condensate KW - electrochemical characterization KW - pitting corrosion KW - impurities KW - carbon steel PY - 2019 UR - https://www.sintef.no/globalassets/project/tccs-10/dokumenter/tccs10---book-of-abstracts.pdf AN - OPUS4-48369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simkin, Roman A1 - Kranzmann, Axel A1 - Pfennig, Anja T1 - Selective oxidation of FeCr and FeCrCo model alloys in dry synthetic air N2 - The life time of mechanical components in high temperature applications is basically determined by their workings. Corrosion determines the loss of material corresponding to the loss of the effective load-bearing section and consequently increasing stress levels. To improve the material selection for such applications a numerical life prediction corrosion model for different alloys and environments is needed. Based on the ferritic alloys FeCr and FeCrCo a first quantitative model is to be developed. For this purpose, the alloys are aged at 600 °C, 650 °C and 700 °C in synthetic air under normal pressure for between 10 and 240 hours. The first objective is to establish a quantitative relationship between the oxidation rate as a function of composition and microstructure of the alloys. The influence of the inner interface as an essential parameter for transport by diffusion on the oxidation kinetics is discussed in this paper. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.11.2019 KW - High temperature corrosion KW - Ooxidation KW - Synthetic air KW - Modeling KW - FeCr- alloys PY - 2019 AN - OPUS4-49465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simkin, Roman A1 - Kranzmann, Axel A1 - Pfennig, Anja A1 - Heide, G. T1 - Oxidation behavior of FeCr model alloys in synthetic air at temperatures above 600 °C N2 - The life time of mechanical components in high temperature applications is basically determined by their workings. Corrosion determines the loss of material corresponding to the loss of the effective load-bearing section and consequently increasing stress levels. To improve the material selection for such applications a numerical life prediction corrosion model for different alloys and environments is needed. Based on the ferritic alloys FeCr and FeCrCo a first quantitative model is to be developed. For this purpose, the alloys are aged at 600°C, 650°C and 700°C in synthetic air under normal pressure for between 10 and 240 hours. The first objective is to establish a quantitative relationship between the oxidation rate as a function of composition and microstructure of the alloys. The influence of the inner interface as an essential parameter for transport by diffusion on the oxidation kinetics is discussed in this presentation. T2 - Gordon Research Conference CY - New London, New Hempshire, USA DA - 21.07.2019 KW - High temperature corrosion KW - Oxidation KW - Synthetic air KW - Modeling KW - FeCr- alloys PY - 2019 AN - OPUS4-49464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Gesell, Stephan T1 - Betriebsfestigkeit von Composite-Wasserstoffspeichern – Ansatz zur Simulation der Auswirkung der erstmaligen Prüfung N2 - Druckbehälter werden vor ihrer Inbetriebnahme obligatorisch einer hydraulischen Prüfung bis zum sog. Prüfdruck belastet. Damit sollen fehlerhaft gefertigte Individuen erkannt und ausgesondert werden. Mit dieser Prüfung werden aber auch diejenigen Einzelbehälter ausgesondert, die ohne einem nachvollziehbaren Fertigungsfehler, nur auf Basis der statistischen Streuung ggf. eine Festigkeit unterhalb des Prüfdrucks aufweisen. Da der Prüfdruck im Fall der Wasserstoffspeicher mindestens 20% über dem maximal zulässigem Betriebsdruck liegt, wäre damit ein Versagen im Betrieb ausgenommen, gäbe es die verschiedenen Alterungs- bzw. Ermüdungseffekt nicht. Um den Einfluss der erstmaligen Prüfung auf eine angenommene ausfallfreie Zeit bewerten zu können, wird hier die Alterung und die erstmalige Prüfung in Kombination analysiert. Hierzu wird auf Basis der Restfestigkeitsdaten aus einer umfangreichen Prüfkampagne ein Ansatz für die Beschreibung der Alterung ermittelt und auf andere Lastzustände übertragen. So kann für das Baumuster, das der o.g. Prüfkampagne zugrunde lag, mithilfe einer Monte-Carlo-Simulation gezeigt werden, dass mindestens 10.000 LW vor einem ersten Alterungsversagen mit 1 aus 1 Mio. In Abhängigkeit der Anzahl der Individuen, die bei der erstmaligen Prüfung versagen, und der Streuung der gesamten Population, kann diese Mindestfestigkeit auf realistisch 50.000 Lastwechsel steigen. Damit ist gezeigt, dass aufgrund der erstmaligen Prüfung eine Mindestfestigkeit erzeugt wird, die stark vom Alterungsverhalten abhängt. Im Ergebnis heißt dies, dass in den Vorschriften aktuell die Bedeutung des Mindestberstdrucks in der Baumusterprüfung überschätzt und die möglichst betriebsbegleitende Erfassung der Alterung unterschätzt sind. T2 - 29. Tagung Technische Zuverlässigkeit- 2019 (02TA502019) CY - Nürtingen bei Stuttgart, Germany DA - 07.05.2019 KW - Mindedestberstdruck KW - Alterung KW - Betriebsfestigkeit KW - Restberstfestigkeit KW - Aussonderugnsrate PY - 2019 AN - OPUS4-48023 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin A1 - Mair, Georg A1 - Gesell, Stephan T1 - Determination of Distribution Function used in MCS on Safety Analysis of Hydrogen Pressure Vessel N2 - The test data of static burst strength and load cycle strength of composite pressure vessels are often described by GAUSSian normal or WEIBULL distribution function to perform safety analyses. The goodness of assumed distribution function plays a significant role in the inferential statistics to predict the population properties by using limited test data. Often, GAUSSian and WEIBULL probability nets are empirical methods used to validate the distribution function; Anderson-Darling and KolmogorovSmirnov tests are the mostly favorable approaches for Goodness of Fit. However, the different approaches used to determine the parameters of distribution function lead mostly to different conclusions for safety assessments. In this study, six different methods are investigated to show the variations on the rates for accepting the composite pressure vessels according to GTR No. 13 life test procedure. The six methods are: a) NormLog based method, b) Least squares regression, c) Weighted least squares regression, d) A linear approach based on good linear unbiased estimators, e) Maximum likelihood estimation and f) The method of moments estimation. In addition, various approaches of ranking function are considered. In the study, Monte Carlo simulations are conducted to generate basic populations based on the distribution functions which are determined using different methods. Then the samples are extracted randomly from a population and evaluated to obtain acceptance rate. Here, the “populations” and “samples” are corresponding to the burst strength or load cycle strength of the pressure vessels made from composite material and a plastic liner (type 4) for the storage of hydrogen. To the end, the results are discussed, and the best reliable methods are proposed. T2 - ICHS2019 Conference CY - Adelaide, Australia DA - 24.09.2019 KW - Monte-Carlo Simulation KW - Distribution function KW - Weibull Distribution PY - 2019 AN - OPUS4-49652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin A1 - Mair, Georg A1 - Gesell, Stephan T1 - Determination of Distribution Function used in MCS on Safety Analysis of Hydrogen Pressure Vessel N2 - The test data of static burst strength and load cycle strength of composite pressure vessels are often described by GAUSSian normal or WEIBULL distribution function to perform safety analyses. The goodness of assumed distribution function plays a significant role in the inferential statistics to predict the population properties by using limited test data. Often, GAUSSian and WEIBULL probability nets are empirical methods used to validate the distribution function; Anderson-Darling and Kolmogorov-Smirnov tests are the mostly favorable approaches for Goodness of Fit. However, the different approaches used to determine the parameters of distribution function lead mostly to different conclusions for safety assessments. In this study, six different methods are investigated to show the variations on the rates for accepting the composite pressure vessels according to GTR No. 13 life test procedure. The six methods are: a) Norm-Log based method, b) Least squares regression, c) Weighted least squares regression, d) A linear approach based on good linear unbiased estimators, e) Maximum likelihood estimation and f) The method of moments estimation. In addition, various approaches of ranking function are considered. In the study, Monte Carlo simulations are conducted to generate basic populations based on the distribution functions which are determined using different methods. Then the samples are extracted randomly from a population and evaluated to obtain acceptance rate. Here, the “populations” and “samples” are corresponding to the burst strength or load cycle strength of the pressure vessels made from composite material and a plastic liner (type 4) for the storage of hydrogen. To the end, the results are discussed, and the best reliable methods are proposed. T2 - ICHS International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - Monte-Carlo Simulation KW - Distribution function KW - Weibull Distribution PY - 2019 SP - 103-1 EP - 103-16 AN - OPUS4-50383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Gesell, Stephan T1 - Betriebsfestigkeit von Composite-Wasserstoffspeichern Erster Ansatz zur Simulation der Auswirkung der erstmaligen Prüfung N2 - Druckbehälter werden vor ihrer Inbetriebnahme obligatorisch einer hydraulischen Prüfung bis zum sog. Prüfdruck belastet. Damit sollen fehlerhaft gefertigte Individuen erkannt und ausgesondert werden. Mit dieser Prüfung werden aber auch diejenigen Einzelbehälter ausgesondert, die ohne einem nachvollziehbaren Fertigungsfehler, nur auf Basis der statistischen Streuung ggf. eine Festigkeit unterhalb des Prüfdrucks aufweisen. Da der Prüfdruck im Fall der Wasserstoffspeicher mindestens 20% über dem maximal zulässigem Betriebsdruck liegt, wäre damit ein Versagen im Betrieb ausgenommen, gäbe es die verschiedenen Alterungs- bzw. Ermüdungseffekt nicht. Um den Einfluss der erstmaligen Prüfung auf eine angenommene ausfallfreie Zeit bewerten zu können, wird hier die Alterung und die erstmalige Prüfung in Kombination analysiert. Hierzu wird auf Basis der Restfestigkeitsdaten aus einer umfangreichen Prüfkampagne ein Ansatz für die Beschreibung der Alterung ermittelt und auf andere Lastzustände übertragen. So kann für das Baumuster, das der o.g. Prüfkampagne zugrunde lag, mithilfe einer Monte-Carlo-Simulation gezeigt werden, dass mindestens 10.000 LW vor einem ersten Alterungsversagen mit 1 aus 1 Mio. In Abhängigkeit der Anzahl der Individuen, die bei der erstmaligen Prüfung versagen, und der Streuung der gesamten Population, kann diese Mindestfestigkeit auf realistisch 50.000 Lastwechsel steigen. Damit ist gezeigt, dass aufgrund der erstmaligen Prüfung eine Mindestfestigkeit erzeugt wird, die stark vom Alterungsverhalten abhängt. Im Ergebnis heißt dies, dass in den Vorschriften aktuell die Bedeutung des Mindestberstdrucks in der Baumusterprüfung überschätzt und die möglichst betriebsbegleitende Erfassung der Alterung unterschätzt sind. T2 - 29. Fachtagung Technische Zuverlässigkeit 2019 CY - Nürtingen, Germany DA - 07.05.2019 KW - Alterung KW - Berstdruck KW - Streuung KW - Degradation KW - statistische Auswertung KW - ausfgallfreie Lastwechsel PY - 2019 SN - 978-3-18-092345-1 SN - 0083-5560 SP - 223 EP - 234 PB - VDI-Verlag GmbH CY - Düsseldorf AN - OPUS4-50181 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pimentel, A. S. O. A1 - Guesser, W. L. A1 - Custódio da Silva, W. J. R. A1 - Portella, Pedro Dolabella A1 - Woydt, Mathias A1 - Burbank, J. T1 - Abrasive wear behavior of austempered ductile iron with niobium additions N2 - Carbidic Austempered Ductile Iron (CADI) microstructures containing eutectic carbides can be produced by the addition of carbide stabilizing elements, such as chromium. Carbides formed from the addition of Cr are eutectic of M3C type. The presence of such hard phases can enhance the abrasion wear resistance of ductile iron. A new CADI can be produced by the addition of Nb. Niobium carbide particles are formed in the beginning of solidification and remain stable once they are insoluble in solid iron matrix. The dry sand abrasive wear resistance of ductile irons alloyed with 1.0, 1.8, and 2.4 wt% Nb were tested in both “as-cast” and “heat treated” conditions using standard ASTM G65. Results were compared to abrasive wear data obtained on ductile iron alloyed with 1 wt% Cr, CADI (1 wt% Cr), and the basic composition of iron without carbide stabilizing elements. In the “ascast” condition, the addition of Nb did not lead to a reduction in wear, while CADI with Nb is a promising substitute for CADI with Cr addition, because both materials showed very similar values of abrasion resistance. Micro-ploughing and micro-cutting mechanisms were observed on the worn surfaces of ductile irons. Abrasive wear resistance of these alloys was correlated with the volume fraction of carbides. KW - arbidic austempered ductile iron KW - Ductile iron KW - Niobium alloying KW - Abrasion PY - 2019 DO - https://doi.org/10.1016/j.wear.2019.203065 VL - 2019 IS - 440–441 SP - 203065 PB - Elsevier CY - Amsterdam, Niederlande AN - OPUS4-50784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Skrotzki, Birgit A1 - Graf, B. A1 - Rethmeier, Michael A1 - Ulbricht, Alexander T1 - Ermüdungsverhalten und Versagensmechanismen von additiv mittels LPA hergestelltem TiAl6V4 N2 - Die Untersuchung und Charakterisierung der Entwicklung/Änderung der Mikrostruktur, der mechanischen Eigenschaften sowie der Lebensdauer additiv gefertigter metallischer Werkstoffe hat bisher, vor allem im Hinblick auf die komplexe Belastungsfälle bei sicherheitsrelevanten Anwendungen, mit der rasanten Entwicklung der Fertigungstechniken nicht Schritt gehalten. Im Rahmen dieser Arbeit wurde eine Charakterisierung des Ermüdungsverhaltens von additiv gefertigten TiAl6V4 im Low-Cycle-Fatigue Bereich (niederzyklische Ermüdung) nach Norm ISO 12206 mit Dehnungsamplituden von 0.3 bis zu 1.0 % und bei Raumtemperatur, 250°C und 400°C durchgeführt. Die TiAl6V4 Proben wurden aus zylindrischen Halbzeugen gefertigt, welche durch Laser-Pulver-Auftragsschweißen mit einer optimierten Aufbaustrategie hergestellt wurden. Die optimierte Aufbaustrategie beinhaltet variierende Spurüberlappungsgraden, die die Fertigung der dünnen zylindrischen Körper ohne weitere Ausgleichslagen ermöglicht. Das Werkstoffverhalten wird anhand von Wechselverformungskurven sowie einer Darstellung der Lebensdauer in einem Wöhler-Diagramm beschrieben. Ein Fitting der Lebensdauer-Daten erfolgt anhand der Manson-Coffin-Basquin Beziehung. Eine Eingangscharakterisierung der mikrostrukturellen Merkmale inklusive Bindefehler aus dem Herstellungsprozess wird durch Lichtmikroskopie und hochauflösende Computertomographie (CT) durchgeführt. Der Versagensmechanismus während der Belastung wird anhand von Zwischenuntersuchungen mit CT und einem unterbrochenen Versuch mit ausgewählten Versuchsparametern beschrieben. Nach dem Versagen wurden die Proben am REM, mit Lichtmikroskopie und mit CT fraktographisch in Längs- und Querrichtung untersucht. Die erfassten Lebensdauern sind ähnlich zu denen aus herkömmlichen Studien und liegen unter derjenigen von dem konventionell hergestellten (geschmiedeten) Werkstoff. In dieser Arbeit wurden für den untersuchten Werkstoff bei anwendungs- und sicherheitsrelevanten Belastungszuständen (hohe Temperaturen, zyklische Plastizität) neue experimentelle Daten und Kennwerte ermittelt und Verständnis über das mechanische Verhalten und die Entwicklung der Mikrostruktur aufgebaut. Darüber hinaus wurde Verständnis über die Rolle von Bindefehlern und anderen typisch für AM auftretenden Gefügemerkmalen auf das Versagensverhalten von DED-L TiAl6V4 gewonnen. T2 - DGM Fachausschuss Titan CY - Liebherr-Aerospace Lindenberg GmbH, Germany DA - 12.11.2019 KW - LCF KW - Titan KW - Ti-6Al-4V KW - Ti64 KW - TiAl5V4 KW - Additive Fertigung KW - CT KW - Mikrostruktur KW - Zugeigenschaften KW - Low Cycle Fatigue PY - 2019 AN - OPUS4-49758 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Zeeuw, C. A1 - Teixeira de Freitas, S. A1 - Zarouchas, D. A1 - Schilling, Markus A1 - Lopes Fernandes, R. A1 - Portella, Pedro Dolabella A1 - Niebergall, Ute T1 - Creep behaviour of steel bonded joints under hygrothermal conditions N2 - The aim of this research is to study the influence of moisture absorption at low moisture contents on the creep behaviour of an epoxy adhesive in steel bonded joints. Single lap joints were manufactured using high strength steel adherends and a two-component epoxy adhesive. The single lap joints were tested at load Levels corresponding to average lap shear stresses of±5%, 15%, 30% and 45% of the dry lap shear strength in both 40 °C air and 40 °C distilled water. Specimens were not pre-aged to be able to analyse the coupled effect of moisture and loading. The test results show that an increase in the load level resulted in an increase in the instantaneous strain and in the creep strain rate. The creep strain of single lap joints loaded in water was generally larger than for the ones loaded in air. For joints loaded in water the creep behaviour was found to be dependent on the moisture concentration in the adhesive. At low moisture percentages creep was suppressed, resulting in a lower instantaneous strain. At higher moisture percentages creep was promoted, resulting in a larger strain rate. The suppression of creep at low moisture percentages is attributed to water molecules bonding to the epoxy macromolecules, resulting in a reduction in molecular mobility and a smaller creep strain. At higher moisture percentages the plasticizing effect of the water dominates, resulting in a larger creep strain. The Maxwell threeelement solid model and Kelvin-Voigt three-element solid model were used to simulate the creep behaviour of the single lap joints loaded in air and water. The models gave good representations of the creep Response across the different load levels in both water and air, they were however unable to give a correct representation of the instantaneous strain of the single lap joints loaded in water. This is attributed to the models being unable to account for the present short-term relaxation process that is dependent on the moisture concentration. KW - C. lap-shear KW - D. aging KW - D. creep D. viscoelasticity KW - Hygrothermal KW - Viscoelastic model PY - 2019 DO - https://doi.org/10.1016/j.ijadhadh.2019.03.002 SN - 0143-7496 VL - 91 SP - 54 EP - 63 PB - Elsevier AN - OPUS4-47538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kindrachuk, Vitaliy A1 - Fedelich, Bernard A1 - Rehmer, Birgit A1 - Peter, Frauke T1 - Computational methods for lifetime prediction of metallic components under high-temperature fatigue N2 - The issue of service life prediction of hot metallic components subjected to cyclic loadings is addressed. Two classes of lifetime models are considered, namely, the incremental lifetime rules and the parametric models governed by the fracture mechanics concept. Examples of application to an austenitic cast iron are presented. In addition, computational techniques to accelerate the time integration of the incremental models throughout the fatigue loading history are discussed. They efficiently solve problems where a stabilized response of a component is not observed, for example due to the plastic strain which is no longer completely reversed and accumulates throughout the fatigue history. The performance of such an accelerated Integration technique is demonstrated for a finite element simulation of a viscoplastic solid under repeating loading–unloading cycles. KW - Fatigue KW - Incremental lifetime models KW - Finite element analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481215 UR - https://www.mdpi.com/2075-4701/9/4/390 DO - https://doi.org/10.3390/met9040390 SN - 2075-4701 VL - 9 IS - 4 SP - 390, 1 EP - 24 PB - mdpi CY - Basel, Switzerland AN - OPUS4-48121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pimentel, A. S. O. A1 - Guesser, W. L. A1 - Portella, Pedro Dolabella A1 - Woydt, Mathias A1 - Burbank, J. T1 - Slip-rolling behavior of ductile and austempered ductile iron containing niobium or chromium N2 - The use of high niobium alloyed cast iron alloys is a relatively new approach in which the niobium addition intends to improve the properties of the material by the precipitation of hard niobium carbides during solidification. Steels can be replaced by ductile cast iron in some rolling applications, such as gears and cams, in order to reduce material costs. The aim of this work is to evaluate ductile iron alloyed with 1 weight percent (wt.%) niobium for the as cast specimens and with 1.8 wt.% and 2.4 wt.% niobium for the austempered specimens under lubricated slip-rolling tests using mixed/boundary conditions in an Amsler-type machine. Austempered ductile iron (ADI) alloyed with 1 wt.% chromium, or Carbidic ADI, was tested for comparison. For the as cast conditions, the niobium addition resulted in an increase of wear resistance owing to the low contact pressure of these tests. However, for the austempered specimens, the best performance was found for unalloyed ADI. The main factor acting in the initiation and propagation of cracks in ductile iron is the presence of the graphite nodules. The coarse carbides also contributed to the initiation of cracks and spalling of the material. KW - Ductile iron KW - Niobium alloying KW - Slip-rolling KW - Carbidic austempered ductile iron PY - 2019 DO - https://doi.org/10.1520/MPC20180188 SN - 2165-3992 SN - 2379-1365 VL - 8 IS - 1 SP - 402 EP - 418 PB - ASTM International CY - West Conshohocken, Pa. AN - OPUS4-51209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - Ta, N. A1 - Skrotzki, Birgit A1 - Darvishi Kamachali, Reza T1 - Chemo-mechanical coupling effect during precipitation in AlLiCu systems N2 - The influence of the chemo-mechanical coupling effect during precipitation in an AlLiCu alloy is presented and discussed. T2 - Plenary meeting DFG Priority program 1713 ("Chemomechanics") CY - Bochum, Germany DA - 19.11.2019 KW - Aluminium KW - Phase-field simulation KW - Chemo-mechanical coupling KW - Transmission electron microscopy PY - 2019 AN - OPUS4-49807 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit A1 - Uckert, Danilo A1 - Kühn, H.-J. A1 - Matzak, Kathrin A1 - Rehmer, Birgit T1 - Ermüdungsverhalten des warmfesten austenitischen Gusseisens EN-GJSA-XNiSiCr35-5-2 bei hoher Temperatur N2 - Die warmfeste austenitische Gusseisenlegierung EN-GJSA-XNiSiCr35-5-2 (häufig auch als Ni-Resist D-5S bezeichnet) wurde hinsichtlich ihres mechanischen Verhal-tens bei hoher Temperatur charakterisiert. Dazu wurden (isotherme) niederzyklische (LCF-) und (nicht-isotherme) thermomechanische Ermüdungsversuche (TMF) zwischen Raumtemperatur und 900 °C durchgeführt. Diese Ergebnisse dienten (zu-sammen mit weiteren Versuchsdaten) der Kalibrierung werkstoffmechanischer Modelle. Bei den höchsten Prüftemperaturen wurde Schädigung in Form von Kriechen beobachtet und metallographisch dokumentiert. T2 - 21. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 06.03.2019 KW - Kriechen KW - LCF KW - TMF KW - Lebensdauer KW - Ni-Resist PY - 2019 AN - OPUS4-47548 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Skrotzki, Birgit A1 - Graf, B. A1 - Rethmeier, Michael A1 - Ulbricht, Alexander T1 - Low cycle fatigue behavior and failure mechanisms of additively manufactured Ti-6Al-4V N2 - Despite of the significant advances in AM process optimization there is still a lack of experimental results and understanding regarding the mechanical behavior and microstructural evolution of AMparts, especially in loading conditions typical for safety-relevant applications e.g. in the aerospace or power engineering. Within the scope of the presented investigations, a characterization of the fatigue behavior of additively manufactured Ti-6Al-4V in the low cycle fatigue regime was carried out in the range of 0.3 to 1.0 % strain amplitude at room temperature, 250°C and 400°C. The Ti-6Al-4V specimens are machined out of lean cylindrical rods, which were fabricated using powder laser metal deposition (LMD) with an improved build-up strategy. The improved strategy incorporates variable track overlap ratios to achieve a constant growth in the shell and core area. The low-cycle-fatigue behavior is described based on cyclic deformation curves and strain-based fatigue life curves. The lifetimes are fitted based on the Manson-Coffin-Basquin relationship. A characterization of the microstructure and the Lack-of-Fusion (LoF)-defect-structure in the as-built state is performed using optical light microscopy and high-resolution computed tomography (CT) respectively. The failure mechanism under loading is described in terms of LoF-defects-evolution and crack growth mechanism based on an interrupted LCF test with selected test parameters. After failure, scanning electron microscopy, digital and optical light microscopy and CT are used to describe the failure mechanisms both in the longitudinal direction and in the cross section of the specimens. The fatigue lives obtained are comparable with results from previous related studies and are shorter than those of traditionally manufactured (wrought) Ti-6Al-4V. In this study new experimental data and understanding of the mechanical behavior under application-relevant loading conditions (high temperature, cyclic plasticity) is gained. Furthermore, a better understanding of the role of LoFdefects and AM-typical microstructural features on the failure mechanism of LMD Ti-6Al-4V is achieved. T2 - First European Conference on Structural Integrity of Additively Manufactured Materials (ESIAM19) CY - Trondheim, Norway DA - 09.09.2019 KW - High Temperature Testing KW - Titanium KW - Ti-6Al-4V KW - Additive Manufacturing KW - Computed Tomography KW - Microstructure KW - Tensile Properties KW - Low Cycle Fatigue PY - 2019 AN - OPUS4-49492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Skrotzki, Birgit A1 - Graf, B. A1 - Rethmeier, Michael A1 - Ulbricht, Alexander T1 - Ermüdungsverhalten und Versagensmechanismen von additiv mittels LPA hergestelltem TiAl6V4 N2 - Die Untersuchung und Charakterisierung der Entwicklung/Änderung der Mikrostruktur, der mechanischen Eigenschaften sowie der Lebensdauer additiv gefertigter metallischer Werkstoffe hat bisher, vor allem im Hinblick auf die komplexe Belastungsfälle bei sicherheitsrelevanten Anwendungen, mit der rasanten Entwicklung der Fertigungstechniken nicht Schritt gehalten. Im Rahmen dieser Arbeit wurde eine Charakterisierung des Ermüdungsverhaltens von additiv gefertigten TiAl6V4 im Low-Cycle-Fatigue Bereich (niederzyklische Ermüdung) nach Norm ISO 12206 mit Dehnungsamplituden von 0.3 bis zu 1.0 % und bei Raumtemperatur, 250°C und 400°C durchgeführt. Die TiAl6V4 Proben wurden aus zylindrischen Halbzeugen gefertigt, welche durch Laser-Pulver-Auftragsschweißen mit einer optimierten Aufbaustrategie hergestellt wurden. Die optimierte Aufbaustrategie beinhaltet variierende Spurüberlappungsgraden, die die Fertigung der dünnen zylindrischen Körper ohne weitere Ausgleichslagen ermöglicht. Das Werkstoffverhalten wird anhand von Wechselverformungskurven sowie einer Darstellung der Lebensdauer in einem Wöhler-Diagramm beschrieben. Ein Fitting der Lebensdauer-Daten erfolgt anhand der Manson-Coffin-Basquin Beziehung. Eine Eingangscharakterisierung der mikrostrukturellen Merkmale inklusive Bindefehler aus dem Herstellungsprozess wird durch Lichtmikroskopie und hochauflösende Computertomographie (CT) durchgeführt. Der Versagensmechanismus während der Belastung wird anhand von Zwischenuntersuchungen mit CT und einem unterbrochenen Versuch mit ausgewählten Versuchsparametern beschrieben. Nach dem Versagen wurden die Proben am REM, mit Lichtmikroskopie und mit CT fraktographisch in Längs- und Querrichtung untersucht. Die erfassten Lebensdauern sind ähnlich zu denen aus herkömmlichen Studien und liegen unter derjenigen von dem konventionell hergestellten (geschmiedeten) Werkstoff. In dieser Arbeit wurden für den untersuchten Werkstoff bei anwendungs- und sicherheitsrelevanten Belastungszuständen (hohe Temperaturen, zyklische Plastizität) neue experimentelle Daten und Kennwerte ermittelt und Verständnis über das mechanische Verhalten und die Entwicklung der Mikrostruktur aufgebaut. Darüber hinaus wurde Verständnis über die Rolle von Bindefehlern und anderen typisch für AM auftretenden Gefügemerkmalen auf das Versagensverhalten von DED-L TiAl6V4 gewonnen. T2 - Werkstoffwoche 2019 CY - Dresden, Germany DA - 18.09.2019 KW - Titan KW - TiAl5V4 KW - Ti-6Al-4V KW - Ti64 KW - Additive Fertigung KW - CT KW - Mikrostruktur KW - Zugeigenschaften KW - Low Cycle Fatigue KW - LCF PY - 2019 AN - OPUS4-49755 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Finn, Monika A1 - Uhlemann, Patrick A1 - Meyer, Christian A1 - Scheuerlein, C. A1 - Amez-Droz, M. A1 - Meuter, F. A1 - Konstantopoulou, K. A1 - Savary, F. A1 - Tock, J.-P. T1 - Thermomechanical properties of polymers for use in superconducting magnets N2 - The coefficient of thermal expansion (CTE) and the thermomechanical properties of the polymers used in superconducting magnets need to be known in order to predict their stress state under the different magnet assembly and operating conditions. We have measured Young’s moduli of typically used polymers during in situ heat cycles with the dynamic resonancemethod. The dynamic test results are compared with Young’s moduli determined from quasi-static stress–strain measurements at room temperature, 77 K and 4.2 K. A moderate elastic anisotropy is found for the fiber reinforced polymers. CTEs are compared based on dilation experiments. TheCTEs of the fiber reinforced polymers studied are similar to those of copper or steel. In contrast, the pure resins exhibit relatively larger CTEs. KW - Polymer KW - Superconducting magnet KW - Young´s modulus KW - Stress-strain behavior KW - Resonance testing KW - Coefficient of thermal expansion PY - 2019 DO - https://doi.org/10.1109/TASC.2019.2898321 SN - 1051-8223 SN - 1558-2515 VL - 29 IS - 5 SP - 7701605, 1 EP - 5 PB - IEEE AN - OPUS4-47616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit A1 - Avila, Luis A1 - Charmi, Amir A1 - Falkenberg, Rainer A1 - Rehmer, Birgit T1 - Mechanical Testing and Simulations on AM Ti6Al4V and 316L N2 - First experimental results are shown on mechanical properties of additively manufactured alloy Ti6Al4V. A modelling and simulation approach is presented to describe the anisotropic behavior of 316L at the macro-scale. T2 - Workshop on Additive Manufacturing: Process, materials, testing, simulation & implants CY - BAM, Berlin, Germany DA - 13.05.2019 KW - AM KW - Mechanical behavior KW - Microstructure KW - Anisotropy KW - Modeling KW - Simulation PY - 2019 AN - OPUS4-48072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Skrotzki, Birgit A1 - Graf, B. A1 - Rethmeier, Michael A1 - Ulbricht, Alexander T1 - Low cycle fatigue behavior, tensile properties and microstructural features of additively manufactured Ti-6Al-4V N2 - Despite of the significant advances in additive manufacturing (AM) process optimization there is still a lack of experimental results and understanding regarding the mechanical behavior and its relationship with the microstructural features of AM-parts, especially in loading conditions typical for safety-relevant applications. Within the scope of the presented ongoing investigations, a basic microstructural characterization, tensile tests at room and elevated temperature (400°C) as well as a characterization of the fatigue behavior of additively manufactured Ti-6Al-4V in the low cycle fatigue regime are carried out in the as-built state. After failure, different techniques are used to describe the failure mechanisms of the specimens. The AM-Specimens are provided by the Fraunhofer institute for production systems and design technology and investigated at the BAM following the philosophy of the TF-Project AGIL. T2 - Workshop on Additive Manufacturing: Process, materials, testing, simulation & implants CY - BAM, Berlin, Germany DA - 13.05.2019 KW - High Temperature Testing KW - Titanium KW - Ti-6Al-4V KW - Additive Manufacturing KW - DED-L KW - LMD KW - Computed Tomography KW - Microstructure KW - Tensile Properties KW - Low Cycle Fatigue PY - 2019 AN - OPUS4-48067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jacobasch, Stefan A1 - Duffner, Eric A1 - Goedecke, Thomas A1 - Portella, Pedro Dolabella A1 - Mair, Georg A1 - Schendler, Thomas A1 - Gradt, Thomas A1 - Askar, Enis A1 - Bartholmai, Matthias A1 - Schröder, Volkmar A1 - Maiwald, Michael A1 - Holtappels, Kai A1 - Tschirschwitz, Rico A1 - Neumann, Patrick P. T1 - Unser Beitrag zum Thema Wasserstoff N2 - Die BAM ist nahezu über die gesamte Wertschöpfungskette hinweg wissenschaftlich tätig. Von der sicheren und effizienten Wasserstofferzeugung (POWER-to-GAS), über die (Zwischen-)Speicherung von Wasserstoff in Druckgasspeichern bis hin zum Transport bspw. mittels Trailerfahrzeug zum Endverbraucher. Komplettiert werden die Aktivitäten der BAM durch die sicherheitstechnische Beurteilung von wasserstoffhaltigen Gasgemischen, die Verträglichkeitsbewertung von Werkstoffen bis hin zur Detektion von Wasserstoffkonzentrationen über geeignete Sensorik, auch mittels ferngesteuerter Messdrohnen (sog. UAV-Drohnen). Zudem untersucht die BAM proaktiv Schadensrisiken und Unfallszenarien für die Sicherheitsbetrachtung, um mögliche Schwachstellen aufzeigen und potenzielle Gefährdungen erkennen zu können. KW - Wasserstoff KW - Wasserstofferzeugung KW - Energiespeicherung KW - Gasdetektion KW - Risikoanalyse KW - Power-to-Gas KW - Explosionsschutz KW - Tribologie KW - Druckgasspeicher KW - Glasspeicher KW - Gassensorik KW - Mini-UAV PY - 2019 SP - 1 CY - Berlin AN - OPUS4-47960 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Corrosion and Fatigue of Heat Treated Martensitic Stainless Steel 1.4542 used for Geothermal Applications N2 - During capture and storage technology (CCS) as well as in geothermal energy production Steels need to withstand the corrosive environment such as: heat, pressure, salinity of the aquifer and CO2-partial pressure. 1.4542 shows unusual corrosion phenomena, but is still sufficiently resistant in corrosive environments. To better understand its behaviour differently heat treated coupons of 1.4542 and for comparison X20Cr13 and X46Cr13 were kept in the artificial brine of the Northern German Basin at T=60 °C. Ambient pressure as well as p=100 bar for 700 h - 8000 h in water saturated supercritical CO2 and CO2-saturated synthetic aquifer Environment was applied. Fatigue tests were performed via push-pull tests with a series of 30 specimens from 150 MPa to 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). FeCO3 and FeOOH are corrosion products also after dynamic corrosion tests. Martensitic microstructure offers good corrosion resistance in geothermal environment. The S-N-curve showing no typical fatigue strength and very steep slopes of possible fatigue strength for finite life. Possible influencing artefacts, such as Al-inclusions could not be correlated to early rupture despite specimens containing inclusions at the fracture surface and cross section reached lower number of cycles. Applied potential proofed to enhance fatigue life tremendously. KW - High Alloyed Steel KW - Pitting KW - Corrosion Fatigue KW - Corrosion KW - Endurance Limit PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503765 DO - https://doi.org/10.20319/mijst.2019.51.138158 SN - 2454-5880 VL - 5 IS - 1 SP - 138 EP - 158 PB - Global Research and Development Services Publishing CY - Rajasthan, India AN - OPUS4-50376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, J. A1 - Terrell, J. A1 - Ferris, L. A1 - Tucker, D. A1 - Leonhardt, T. A1 - Goldbeck, Hennig T1 - Low-Cost Fabrication of Tungsten-Rhenium Alloys for Friction Stir Welding Applications N2 - Friction stir welding (FSW) of high-melting temperature alloys, such as steel and Inconel, requires tooling that can survive under the applied loads at the elevated temperatures. Tungsten-Rhenium (W-Re) alloys are a suitable candidate for this application; however, the costs typically associated with achieving the required densities and grain structure for the tooling are high due to the lengthy traditional processing required. Further costs are incurred in machining the starting bar stock to the final FSW tooling configuration. An alternate processing method is used in this study to shorten the fabrication time using direct current sintering which rapidly consolidates the starting powders at lower temperatures than used in traditional powder metallurgy. Although this process enables retention of the fine grain size, the sintering time is too short to form the desired single, solid phase. Therefore, the specimens were subjected to a post-consolidation heat treatment to fully solutionize the W matrix. Once the desired density and solid solution phase was verified in coupons, the final processing parameters were used to consolidate a net shape tool for FSW. KW - Tungsten-Rhenium KW - Friction Stir Welding KW - Fabrication PY - 2019 DO - https://doi.org/10.1007/s11663-019-01726-6 VL - 51 IS - 1 SP - 35 EP - 44 PB - Springer AN - OPUS4-50027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Wolf, M. A1 - Kranzmann, Axel T1 - The role of surface texture on the corrosion fatigue behavior of high alloyed stainless steel exposed to saline aquifer water environment N2 - Corrosion fatigue specimen with different surfaces (technical surfaces after machining and polished surfaces) of high alloyed martensitic stainless steel X46Cr13 (1.4043) and duplex stai nless steel X2CrNiMoN22 3 2 (1.4462) were compared at load amplitudes from 175 MPa to 325 MPa in the geothermal brine of the N orthern German Basin at 98 °C. Surface corrosion layers and pits reveal carbonate corrosion products on the surface such as FeCO 3 and FeOOH as the main precipitation phases with no dependence on the original surface roughness . At high stress amplitudes above 275 MPa technical surfaces (P50% at σa 300 MPa=5 × 10 5 ) resulted in more cycles to failure than polished (P50% at σa 300 MPa=1.5 × 10 5 ). The greater slope coefficient for technical surfaces k = 19.006 compared to polished surfaces k =8.78 demonstrate s earlier failure at given stress amplitude σa . KW - Corrosion KW - CCS KW - Carbon storage KW - Aquifer KW - Heat treatment PY - 2019 DO - https://doi.org/10.17706/ijmse SN - 2315-4527 VL - 7 IS - 2 SP - 26 EP - 33 PB - IAP - International Academy Publishing CY - San Bernardino, CA AN - OPUS4-50365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Effect of CO2 gas on carbon steel corrosion in an acidic-saline based geothermal fluid N2 - Geothermal energy is one of the most promising energy resources to replace fossil fuel. To extract this energy, hot fluids of various salts and gases are pumped up from a geothermal well having a certain depth and location. Geothermal wells in volcanic regions often contain highly corrosive CO2 and H2S gases that can be corrosive to the geothermal power-plants, which are commonly constructed of different steels, such as carbon steel. This research focuses on the corrosion behaviour of carbon steel exposed to an artificial geothermal fluid containing CO2 gas, using an artificial acidic-saline geothermal brine as found in Sibayak, Indonesia. This medium has a pH of 4 and a chloride content of 1,500 mg/L. Exposure tests were conducted for seven days at 70 °C and 150 °C to simulate the operating temperatures for low and medium enthalpy geothermal sources. Surface morphology and cross-section of the specimens from the above experiments were analysed using scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Electrochemical tests via open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) were performed to understand the corrosion processes of carbon steel in CO2-containing solution both at 70 °C and 150 °C. Localized corrosion was observed to a greater extent at 70 °C due to the less protectiveness of corrosion product layer compared to that at 150 °C, where FeCO3 has a high corrosion resistance. However, a longer exposure test for 28 days revealed the occurrence of localized corrosion with deeper pits compared to the seven-day exposed carbon steel. In addition, corrosion product transformation was observed after 28 days, indicating that more Ca2+ cations incorporate into the FeCO3 structure. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Carbon steel KW - CO2 KW - EIS KW - Geothermal KW - Corrosion PY - 2019 SP - Paper 200245, 1 EP - 5 CY - Madrid, Spain AN - OPUS4-49099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Schiller, B.N. A1 - Beck, M. A1 - Bettge, Dirk T1 - On the corrosion behaviour of co 2 injection pipe steels: role of cement N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost-effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells, the corrosion resistance of the materials used needs to be determined. In this study, representative low-cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were investigated in simulated pore water at 333 K and under CO2 saturation condition to represent the worst-case scenario: CO2 diffusion and aquifer fluid penetration. These simulated pore waters were made from relevant cement powder to mimic the realistic casing-cement interface. Electrochemical studies were carried out using the pore water made of cement powder dissolved in water in comparison with those dissolved in synthetic aquifer fluid, to reveal the effect of cement as well as formation water on the steel performance. Two commercially available types of cement were investigated: Dyckerhoff Variodur® and Wollastonite. Variodur® is a cement containing high performance binder with ultra-fine blast furnace slag which can be used to produce high acid resistance concrete. On the other hand, Wollastonite is an emerging natural material mainly made of CaSiO3 which can be hardened by converting to CaCO3 during CO2 injection. The results showed the pH-reducing effect of CO2 on the simulated pore water/aquifer (from more than 10 to less than 5) leading to the active corrosion process that happened on both 1.8977 and 1.7225. Electrochemical characterization showed negative free corrosion potential and polarisation curves without passive behaviors. The tested coupons suffered from pitting corrosion, which was confirmed by surface analysis. Interestingly, basing on the pit depth measurements from the tested coupons and the hardness of cement powder, it is suggested that Variodur® performed better than Wollastonite in both aspects. The electrochemical data was compared to that resulted from exposure tests to give a recommendation on material selection for bore-hole construction. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Cement KW - Carbon capture KW - Corrosion and storage (CCUS) technology KW - Utilization KW - Carbon steel KW - Crevice corrosion PY - 2019 SP - Paper 200597, 1 EP - 4 PB - SOCIEMAT CY - Madrid, Spain AN - OPUS4-49109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Effect of CO2, atmosphere and pressure on the stability of C35CrMo17 stainless steel in laboratory CCS-environment N2 - During carbon sequestration the CO2-induced corrosion of injection pipe steels is a relevant safety issue when emission gasses are compressed into deep geological layers. The reliability of the high alloyed steel X35CrMo17 suitable as injection pipe for the geological onshore CCS-site (Carbon Capture and Storage) in the Northern German Basin, is demonstrated in laboratory experiments in equivalent corrosive environment (T = 60 °CC, p = 1–100 bar, aquifer water, CO2-flow rate of 9 L/h, 700–8000 h exposure time). Corrosion kinetics and microstructure were characterized and compared to other potential injection pipe steels (42CrMo4, X46Cr13, X20Cr13 and X5CrNiCuNb16-4). T2 - 14th Greenhouse Gas Control Technologies Conference CY - Melbourne, Australia DA - 21.10.2018 KW - Steel KW - Supercritical CO2 KW - Pipeline KW - Corrosion KW - CO2-storage PY - 2019 SP - 1 EP - 9 PB - Elsevier Ltd. AN - OPUS4-50382 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, A. A1 - Gröber, A. A1 - Kranzmann, Axel T1 - The Role of Surface Texture on the Corrosion Behavior of High Alloyed Steel Exposed to Saline Aquifer Water Environments N2 - Coupons of X5CrNiCuNb16-4 that may be used as injection pipe with 16% Chromium and 0.05% Carbon (1.4542, AISI 630) were exposed for 3000 h to CO2-saturated saline aquifer water similar to the conditions in the Northern German Basin at ambient pressure and 60 °C. Surface corrosion layers and pits reveal carbonate corrosion products on the surface such as FeCO3 and FeOOH as the main precipitation phases with no dependence on the original surface roughness. Corrosion rates for polished and technical surfaces were below 0.005 mm/year compared to corrosion rates of 0.035 mm/year after shot peening. T2 - 14th Greenhouse Gas Control Technologies Conference CY - Melbourne, Australia DA - 21.10.2018 KW - High alloyed steel KW - Pitting KW - Surface KW - Roughness KW - CO2 PY - 2019 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-50375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Electrochemical deposition of polyaniline on carbon steel for corrosion study in geothermal solution N2 - Polyaniline has been widely developed for many applications, e.g. sensor, supercapacitor components, electrochromic devices, and anticorrosion pigments. Although the addition of polyaniline pigment in organic coatings has been an alternative for corrosion protection in industrial applications, the protection mechanism is still not fully understood. Herein in this study, as a part of the development of polyaniline/silicon dioxide coating for geothermal application, polyaniline has been deposited electrochemically on carbon steel surface in oxalic acid medium and tested in geothermal solution to understand the contribution of polyaniline to the corrosion protection of a polyaniline-based composite in the geothermal system. To observe the surface/interface reaction between the electrolyte and electrode surface during the electrochemical polymerization, electrochemical impedance spectroscopy (EIS) was applied after each cycle. For corrosion study in the geothermal application, an artificial geothermal solution was used with the composition of 1,500 mg/l Cl⁻, 20 mg/l SO₄²⁻, 15 mg/l HCO₃⁻, 200 mg/l Ca²⁺, 250 mg/l K⁺, and 600 mg/l Na⁺, and pH 4 to simulate a geothermal brine found in Sibayak, Indonesia. An electrochemical measurement was performed by monitoring the open circuit potential over seven days, with the interruption by EIS every 22 hours. The experiments were performed at room temperature and 150 °C (1 MPa) in an oxygen-free environment. Impedance spectra showed a reduction of the total impedance value of approximately 10 times for specimens measured at 150 °C compared to the specimens measured at room temperature, suggesting a less stable layer at high temperature. KW - Corrosion KW - Electrochemical deposition KW - Polyaniline PY - 2019 DO - https://doi.org/10.4028/www.scientific.net/MSF.966.107 SN - 1662-9752 VL - 966 SP - 107 EP - 115 PB - Trans Tech Publications Ltd CY - Zürich AN - OPUS4-48776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Yevtushenko, Oleksandra A1 - Bettge, Dirk T1 - Corrosion Aspects for Materials to be Used in CC(U)S Applications N2 - This contribution provides current findings regarding materials susceptibility for carbon capture, utilization and storage (CCUS) applications. Basing on results gathered in 2 German long-term projects (COORAL and CLUSTER) suitable materials are introduced as well as dominating impurities of the CO2-stream and corrosion mechanisms. Investigations cover the whole CCUS process chain and provide material recommendations for certain parts. T2 - 1st International Conference on Corrosion Protection and Application CY - Chongqing, China DA - 09.10.2019 KW - Carbon KW - Capture KW - Storage KW - Utilization KW - CCS KW - CCU KW - CO2 KW - Corrosion KW - Steel PY - 2019 SP - Paper 31 PB - Chinese Society for Corrosion and Protection CY - Chongqing/China AN - OPUS4-49301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Nolze, Gert A1 - Roohbakhshan, Farshad A1 - Fedelich, Bernard A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic operation performance of 9-12% Cr ferritic-martensitic steels part 2: Microstructural evolution during cyclic loading and its representation in a physically-based micromechanical model N2 - The current competitive situation on electricity markets forces conventional power plants into cyclic operation regimes with frequent load shifts and starts/shutdowns. In the present work, the cyclic mechanical behavior of ferritic-martensitic 9-12 % Cr steels under isothermal and thermomechanical loading was investigated for the example of grade P92 material. A continuous softening was observed under all loading conditions. The introduction of hold periods to the applied cycles reduced material lifetime, with most prominent effects at technologically relevant small strain levels. The microstructural characterization reveals a coarsening of the original “martensitic” lath-type microstructure to a structure with polygonal subgrains and reduced dislocation density. The microstructural data forms the input for a physically-based modelling approach. T2 - 45. MPA-Seminar CY - Leinfelden-Echterdingen, Germany DA - 01.10.2019 KW - Tempered Martensite Ferritic Steels KW - P92 KW - TEM KW - EBSD KW - Micromechanical model PY - 2019 SP - 80 EP - 85 PB - MPA (Materialprüfungsanstalt Universität Stuttgart) CY - Stuttgart AN - OPUS4-50052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Winkelmann, A. A1 - Britton, T. B. A1 - Nolze, Gert T1 - EBSD Kikuchi Pattern Analysis, Silicon 15kV N2 - Supplementary data and images for Si EBSD pattern analysis as presented in: A. Winkelmann, T.B. Britton, G. Nolze "Constraints on the effective electron energy spectrum in backscatter Kikuchi diffraction", Physical Review B (2019). KW - EBSD KW - Electron energy KW - Energy distribution KW - Kikuchi pattern KW - Simulation PY - 2019 DO - https://doi.org/10.5281/zenodo.2565061 PB - Zenodo CY - Geneva AN - OPUS4-51907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Corrosion of Carbon Steel in Artificial Geothermal Brine: Influence of Carbon Dioxide at 70 °C and 150 °C N2 - This study focuses on the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by carbon dioxide (CO2) gas. The tested brine simulates a geothermal source in Sibayak, Indonesia, containing 1500 mg/L of Cl-, 20 mg/L of SO4 2-, and 15 mg/L of HCO3-with pH 4. To reveal the temperature effect on the corrosion behavior of carbon steel, exposure and electrochemical tests were carried out at 70 °C and 150 °C. Surface analysis of corroded specimens showed localized corrosion at both temperatures, despite the formation of corrosion products on the surface. After 7 days at 150 °C, SEM images showed the formation of an adherent, dense, and crystalline FeCO3 layer. Whereas at 70 °C, the corrosion products consisted of chukanovite (Fe2(OH)2CO3) and siderite (FeCO3), which are less dense and less protective than that at 150 °C. Control experiments under Ar-environment were used to investigate the corrosive effect of CO2. Free corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) confirm that at both temperatures, the corrosive effect of CO2 was more significant compared to that measured in the Ar-containing solution. In terms of temperature effect, carbon steel remained active at 70 °C, while at 150 °C, it became passive due to the FeCO3 formation. These results suggest that carbon steel is more susceptible to corrosion at the near ground surface of a geothermal well, whereas at a deeper well with a higher temperature, there is a possible risk of scaling (FeCO3 layer). A longer exposure test at 150 °C with a stagnant solution for 28 days, however, showed the unstable FeCO3 layer and therefore a deeper localized corrosion compared to that of seven-day exposed specimens. KW - Carbon steel KW - CO2 KW - Corrosion KW - Electrochemical impedance spectroscopy KW - Geothermal PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498168 DO - https://doi.org/10.3390/ma12223801 SN - 1996-1944 VL - 12 IS - 22 SP - 3801-1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-49816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kratzig, Andreas A1 - Bettge, Dirk A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Kranzmann, Axel T1 - Interaction of Oxidizing and Reductive Components in CO2 Streams with Transport Pipeline Steel X70 at High Pressure and Low Temperature N2 - Specific amounts of oxidizing and reductive impurities as well as some moisture were added to dense phase CO2 to replicate CO2 streams from sources in a CCS pipeline network. Due to the moisture content being only 50 ppmV no visible acid condensation took place. To simulate stress conditions at the inside pipeline surface due to fluid pressure (10 MPa) specimens were preloaded using a load frame. Experiments conducted at 278 K and at 313 K revealed the highest corrosion rate at lower temperature. Corrosive effect of impurities was strongest applying mixed atmosphere, containing oxidizing and reductive components, closely followed by CO2 streams with pure oxidizing character. By far, the lowest corrosion rate (10x lower) resulted from reductive atmosphere. In general, at constant temperature and pressure the CO2 stream composition strongly influences the morphology, thickness and composition of the corrosion products. Applying oxidizing or mixed impurities, iron hydroxides or oxides (e.g. goethite, hematite) occur as dominating corrosion products, capable to incorporate different amounts of sulfur. In contrast, using reductive atmosphere very thin corrosion layers with low crystallinity were developed, and phase identification by XRD was unfeasible. SEM/EDX analysis revealed the formation of Fe-O compounds, most likely attributed to the oxygen partial pressure in the system induced by CO2 (≥0.985 volume fraction) and volatile H2O. In addition to the surface covering corrosion layer, secondary phases had grown locally distributed on top of the layer. These compounds are characteristic for the applied atmosphere and vary in number, shape and chemical composition. T2 - 14th Greenhouse Gas Control Technologies Conference (GHGT-14) CY - Melbourne, Australia DA - 21.10.2018 KW - CCS KW - CO2 Corrosion KW - Pipelines PY - 2019 UR - https://ssrn.com/abstract=3365756 VL - 2019 SP - 1 EP - 15 AN - OPUS4-49711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Bettge, Dirk A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Kranzmann, Axel T1 - Abschlussbericht des Projektteils CLUSTER - BAM: Werkstoffauswahl und Festlegung von Obergrenzen für Verunreinigungen in variierenden CO2-Strömen auf Grund von realitätsnahen Korrosionsexperimenten - FKZ 03ET7031C - im Projektverbund CLUSTER: Auswirkungen der Begleitstoffe in den abgeschiedenen CO2‐Strömen unterschiedlicher Emittenten eines regionalen Clusters auf Transport, Injektion und Speicherung N2 - Nachdem im Verbundprojekt COORAL das Hauptaugenmerk auf überkritisches CO2 gelegt wurde, d. h. Transport über kurze Strecken bei erhöhter Temperatur, wurde in CLUSTER ein größeres lokales Transport-Netzwerk betrachtet, bei dem CO2 bei geringeren Temperaturen, also vorwiegend im flüssigen Zustand transportiert wird. Wurden in COORAL die CO2-Ströme von Kohlekraftwerken untersucht, ging es in CLUSTER zusätzlich um die Emissionen von relevanten Industrien, deren CO2-Emissionen nicht ohne Weiteres vermieden werden können. Aufgrund der Erfahrungen in COORAL konnte eine Auswahl von kommerziellen Werkstoffen getroffen werden, die für einen konkreten Einsatz für CCS zur Verfügung stünden. Die gemischten und fluktuierenden CO2-Zusammensetzungen sind bei geeigneten Begrenzungen der Begleit¬stoffe im CO2 bezüglich Korrosionsvorgänge beherrschbar. Die Machbarkeit eines lokalen CCS-Clusters erscheint daher gegeben, soweit dies die Anlagen für Kompression, Transport und Injektion betrifft. KW - CCS KW - Korrosion KW - CO2-Speicherung KW - Pipelines PY - 2019 SP - 1 EP - 67 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-50249 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Heide, K. T1 - Roaldite in the iron-meteorite São Julião de Moreira N2 - Roaldite – Fe4N – has been identified in the São Julião de Moreira iron meteorite using electron backscatter diffraction (EBSD) and simultaneously acquired energy-dispersive x-ray spectroscopy (EDS). Mean-periodic-number images derived from raw EBSD patterns confirm this phase by an even higher spatial resolution compared to EDS. Roaldite appears in the form of systematically and repetitively aligned plates. Despite the locally heavy plastic deformation, it is shown that the origin of the oriented precipitation of roaldite is linked to the orientation of the kamacite matrix. Roaldite can be considered to be precipitated from kamacite using an inverse Kurdjumov-Sachs (K-S) or Nishiyama-Wassermann (N-W) orientation relationship. A more accurate discrimination is impossible due to the accumulated shock deformation, which blurs the local reference orientation of kamacite. The habit plane of roaldite is found to be {112}R, which is most likely parallel to {120}K of kamacite. Some of the roaldite plates contain two orientation variants which repeatedly alternate. Their misorientation angle is about 12°. KW - Plastic deformation KW - Iron meteorite KW - Corrosion KW - Nitride KW - Orientation relationship PY - 2019 DO - https://doi.org/10.1016/j.chemer.2019.125538 VL - 79 IS - 4 SP - 125538 PB - Elsevier AN - OPUS4-50338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Bettge, Dirk T1 - On the corrosion mechanism of CO2 transport pipeline steel caused by condensate: Synergistic effects of NO2 and SO2 N2 - To study the effects of condensed acid liquid, hereafter referred to as condensate, on the CO2 transport pipeline steels, gas mixtures containing a varying concentration of H2O, O2, NO2, and SO2, were proposed and resulted in the condensate containing H2SO4 and HNO3 with the pH ranging from 0.5 to 2.5. By exposing the pipeline steel to the synthetic condensate with different concentration of acidic components, the corrosion kinetic is significantly changed. Reaction kinetic was studied using electrochemical methods coupled with water analysis and compared with surface analysis (scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometry (XRD)) of corroded coupons. The results showed that, although the condensation of NO2 in the form of HNO3 causes faster general corrosion rate, it is the condensation of SO2 in the form of H2SO4 or the combination of SO2 and NO2 that may cause much more severe problems in the form of localized and pitting corrosions. The resulting corrosion forms were depended on the chemical nature of acids and their concentration at the same investigated pH. The effects of changing CO2 flow rate and renewing condensate on pitting corrosion were further studied. KW - Carbon capture, utilization and storage technology KW - CCUS KW - Corrosion KW - Condensate KW - Electrochemical characterisation KW - Pitting corrosion KW - Impurities KW - Carbon steel PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473685 UR - https://www.mdpi.com/1996-1944/12/3/364 DO - https://doi.org/10.3390/ma12030364 SN - 1996-1944 VL - 12 IS - 3 SP - 364, 1 EP - 17 PB - MDPI CY - Basel AN - OPUS4-47368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falk, Florian A1 - Menneken, M. A1 - Stephan-Scherb, Christiane T1 - Real-time observation of high- temperature gas corrosion in dry and wet SO2-containing atmosphere N2 - Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This paper investigates the effect of water vapor in the initial stages of SO2 corrosion of an Fe-9Cr-0.5Mn model alloy at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale–alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere. KW - Early oxidation KW - Early sulfidation KW - Ferritic steels PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472844 UR - https://link.springer.com/article/10.1007/s11837-019-03335-9#enumeration DO - https://doi.org/10.1007/s11837-019-03335-9 SN - 1047-4838 SN - 1543-1851 VL - 71 SP - 1 EP - 6 PB - Springer CY - New York AN - OPUS4-47284 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Klinger, Christian A1 - Bettge, Dirk A1 - Murakami, Y. T1 - Defects as a root cause of fatigue failure of metallic components. III: Cavities, dents, corrosion pits, scratches N2 - This third part of the review on defects as root cause of fatigue failure addresses cavities (pores, micro-shrinkages, unmelted regions), defective microstructures and microcracks as material defects and defects due to local damage during manufacturing, service and maintenance such as dents, scratches and localized corrosion. In addition, damage due to contact fatigue and the effect of surface roughness are discussed in the context of fatigue failure. Also addressed is the competition between different kinds of defects in controlling the initiation and early growth of fatigue cracks. KW - Pores KW - Micro-shrinkages KW - Impact damage KW - Contact fatigue KW - Corrosion pits KW - Scratches PY - 2019 DO - https://doi.org/10.1016/j.engfailanal.2019.01.034 SN - 1350-6307 VL - 97 SP - 759 EP - 776 PB - Pergamon-Elsevier Science Ltd CY - Oxford, England AN - OPUS4-47373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Klinger, Christian A1 - Bettge, Dirk A1 - Murakami, Y. T1 - Defects as a root cause of fatigue failure of metallic components. I: Basic aspects N2 - According to the definition of the ASM handbook [1,3], a defect is "an imperfection. that can be shown to cause failure by a quantitative analysis and that would not have occurred in the absence of the imperfection". The topic of the present three-part review is a discussion of defects which can cause failure in cyclically loaded structures. The features discussed comprise material defects such as non-metallic inclusions, pores or micro-shrinkages, etc. and geometric defects such as surface roughness and secondary notches which have their origin in manufacturing, and defects such as surface damage due to scratches, impact events or contact fatigue as well as corrosion pits which arise in service. In this first part, the discussion is prefaced by an introduction to basic aspects which are essential for a deeper understanding of the characteristics and mechanisms how the defects influence fatigue crack initiation and propagation. These include the life cycle of a fatigue crack from initiation up to fracture, crack arrest, multiple crack initiation and coalescence, and the material and geometrical properties affecting these. KW - Defects KW - Fatigue crack propagation stages KW - Crack arrest KW - Multiple cracks PY - 2019 DO - https://doi.org/10.1016/j.engfailanal.2019.01.055 SN - 1350-6307 VL - 97 SP - 777 EP - 792 PB - Pergamon-Elsevier Science Ltd CY - Oxford, England AN - OPUS4-47372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Klinger, Christian A1 - Bettge, Dirk A1 - Murakami, Y. T1 - Defects as a root cause of fatigue failure of metallic components. II: Non-metallic inclusions N2 - This second part of the review on defects as root cause of fatigue failure comprises the origin, the nature and the effects of non-metallic inclusions. Topics addressed are the different kinds of inclusions formed during the manufacturing process, various types of mis-match causing local stresses and, as a consequence, fatigue crack initiation, and effects of characteristics such as size, morphology, localization, spatial distribution and orientation of the defects on the fatigue behavior. Methods for inclusion counting and sizing are discussed along with statistical aspects necessary to be considered when evaluating structural components. KW - Non-metallic inclusions KW - Mis-match KW - Inclusion size KW - Inclusion cluster KW - Statistics PY - 2019 DO - https://doi.org/10.1016/j.engfailanal.2019.01.054 SN - 1350-6307 VL - 98 SP - 228 EP - 239 PB - Elsevier Ltd. AN - OPUS4-47459 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chandra, K. A1 - Dörfel, Ilona A1 - Wollschläger, N. A1 - Kranzmann, Axel T1 - Microstructural investigation using advanced TEM techniques of inner ocide layers formed on T92 steel in oxyfuel environment N2 - T92 steel was oxidized at 650 °C for 1000 h in dry and wet oxyfuel gases. The microstructure of inner oxide layer was investigated using scanning transmission electron microscopy and energy dispersive spectroscopy on thin lamellas of oxide cross-sections. The oxides were composed of fine equiaxed grains and separated into Fe-rich and Cr-rich regions. Fe-rich regions were wustite and iron sulphide while Cr-rich regions consisted of Fe-Cr spinel with different stoichiometries. Precipitates of (W,Mo)-rich oxides were formed within the oxide scale and beneath the oxide/alloy interface. Often iron sulphide and (W,Mo)-rich oxide were surrounded by Cr-rich spinel. KW - Steel KW - STEM KW - High temperature corrosion KW - Oxidation KW - Internal oxidation PY - 2019 DO - https://doi.org/10.1016/j.corsci.2018.12.008 SN - 0010-938X SN - 1879-0496 VL - 148 SP - 94 EP - 109 PB - Elsevier AN - OPUS4-47423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Saliwan Neumann, Romeo A1 - Reith, F. A1 - Etschmann, B. A1 - Kilburn, M. R. A1 - Brugger, J. T1 - Unravelling the formation histories of placer gold and platinum-group mineral particles from Corrego Bom Successo, Brazil: A window into noble metal cycling N2 - Gold and platinum-group-metals (PGM) are cycled through Earth's environments by interwoven geological, physical, chemical and biological processes leading to the trans/neoformation of metallic particles in placers. The placer deposit at Corrego Bom Successo (CBS, Brazil) is one of the few localities worldwide containing secondary gold- and PGM-particles. Placer gold consists of detrital particles from nearby hydrothermal deposits that were transformed in the surface environment. Processes that have affected these particles include shortdistance transport, chemical de-alloying of the primary Gold silver, and (bio)geochemical dissolution/reprecipitation of Gold leading to the formation of pure, secondary gold and the Dispersion of gold nanoparticles. The latter processes are likely mediated by non-living organic matter (OM) and bacterial biofilms residing on the particles. The biofilms are largely composed of metallophillic β- and γ-Proteobacteria. Abundant mobile gold and platinum nanoparticles were detected in surface waters, suggesting similar mobilities of these metals. Earlier hydrothermal processes have led to the formation of coarsely-crystalline, arborescent dendritic potarite (PdHg). On potarite surfaces, biogeochemical processes have then led to the formation of platinum- and palladium-rich micro-crystalline layers, which make up the botryoidal platinum palladium aggregates. Subsequently potarite was dissolved from the core of many aggregates leaving voids now often filled by secondary anatase (TiO2) containing biophilic elements. The presence of fungal structures associated with the anatase suggests that fungi may have contributed to ist formation. For the first time a primary magmatic PGM-particle comprising a mono-crystalline platinum palladium-alloy with platinum iridium osmium inclusions was described from this locality, finally defining a possible primary source for the PGM mineralisation. In conclusion, the formation of modern-day placer gold- and PGM-particles at CBS began 100s ofmillions of years ago bymagmatic and hydrothermal processes. These provided the metal sources for more recent biogeochemical cycling of PGEs and gold that led to the trans/neoformation of gold- and PGM-particles. KW - Gold KW - Platinum-group-metals KW - Biogeochemical cycling KW - Magmatic and hydrothermal processes KW - Biomineralisation PY - 2019 DO - https://doi.org/10.1016/j.gr.2019.07.003 SN - 1342-937X VL - 76 SP - 246 EP - 259 PB - Elsevier AN - OPUS4-48657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, A. A1 - Gröber, A. A1 - Simkin, Roman A1 - Kranzmann, Axel T1 - Influence of Surface Quality on the Corrosion and Corrosion Fatigue Behavior of High Alloyed Steels Exposed to Different Saline Aquifer Water Environment N2 - Coupons of X5CrNiCuNb16-4 with different surface roughness that may be utilized as injection pipe with 16% Chromium and 0.05% Carbon (1.4542, AISI 630) were exposed for 3000 h to CO2-saturated saline aquifer water simulating the conditions in the Northern German Basin at ambient pressure and 60 °C. Additionally, corrosion fatigue experiments (ambient pressure, technically clean CO2, saline aquifer water of Stuttgart Aquifer) were performed using specimen of X46Cr13 (1.4043, AISI 420C) with regard to the influence of the roughness of technical surfaces on the number of cycles to failure at different stress amplitudes. Specimen of Duplex stainless steel X2CrNiMoN22-3-2 (1.4462) for corrosion fatigue experiments were provided with technical surfaces after machining as well as polished surfaces. Results were obtained at load amplitudes ranging from 175 MPa to 325 MPa in the geothermal brine of the Northern German Basin at 98 °C. The main precipitation phases on the surface as well as within pits reveal carbonates or hydroxides such as siderite (FeCO3) and ferrous hydroxide goethite (FeOOH) independent of the original surface roughness. Corrosion rates for polished and technical surfaces were below 0.005 mm/year compared to corrosion rates of 0.035 mm/year after shot peening. Specimen with technical surfaces tested at high stress amplitudes (>275 MPa) lasted longer (cycles to failure: P50% at Sa 300 MPa=5x105) than specimen with polished surfaces (cycles to failure: P50% at Sa 300 MPa=1.5x105). This behavior is emphasized by the slope coefficient (technical surfaces k = 19.006, polished surfaces k=8.78) meaning earlier failure for polished at high stress amplitude Sa. Although rather low scatter ranges (technical surface: TN=1:1.35, polished surface: TN=1.1.95) indicate no change in failure mechanism it may be assumed that at low stress pitting is the initiating crack growth process whereas at high stress amplitudes the formation of micro cracks is reason for crack propagation and failure. KW - High Alloyed Steel KW - Pitting KW - Surface KW - Roughness KW - Corrosion Fatigue PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503772 DO - https://doi.org/10.20319/mijst.2019.51.115137 SN - 2454-5880 VL - 5 IS - 1 SP - 115 EP - 137 PB - Global Research and Development Services Publishing CY - Rajasthan, India AN - OPUS4-50377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knauer, S A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Jaeger, P T1 - Contact angle and corrosion of a Water – CO2 system on X70 and S41500 at 278 K and pressures up to 20 MPa N2 - Interfacial properties related to wettability and corrosion in CO2 transport pipelines are experimentally determined by the sessile and the pendant drop methods. The contact angle of a water drop in a compressed CO2 atmosphere is analyzed on an X70 pipeline carbon steel and compared to that on a martensitic steel S41500 to elucidate the effect of corrosion process on active wetting behaviour. The measurements are performed with liquid CO2 at 278 K and pressures ranging from 5 to 20 MPa. The results show that the contact angle (CA) increases with pressure from 132 ° to 143 ° for S41500 and from 117 ° to 137 ° for X70 and decreases with drop age by 20 ° to 24 ° regardless of the pressure and of the fact that corrosion only occurs on X70, which is confirmed by scanning electron microscopy, element mapping and energy dispersive x-ray spectrometry (EDS) analysis. At higher pressure, the contact angles on both materials converge. Further, related properties like density and interfacial tension were determined. CO2 - saturated water has a higher density than pure water: At 5 MPa saturated water reaches a density of 1017 kg⋅m^(-3) and at 20 MPa 1026 kg⋅m^(-3) compared to pure water with a density of 1002 kg⋅m^(-3) and 1009 kg⋅m^(-3), respectively. In this pressure range the IFT drops from 33 mN⋅m^(-1)at 5 MPa to 23 mN⋅m^(-1) at 20 MPa. KW - Carbon capture KW - Utilization, and storage (CCUS) technology KW - Contact angle KW - Wetting KW - Corrosion KW - Condensate KW - Impurities KW - Carbon steel PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S1750583618309472?dgcid=author DO - https://doi.org/10.1016/j.ijggc.2019.06.021 SN - 1750-5836 SN - 1878-0148 VL - 89 SP - 33 EP - 39 PB - Elsevier, ScienceDirect AN - OPUS4-48601 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Winkelmann, A. A1 - Britton, T. B. T1 - Constraints on the effective electron energy spectrum in backscatter Kikuchi diffraction N2 - Electron backscatter diffraction (EBSD) is a technique to obtain microcrystallographic information from materials by collecting large-angle Kikuchi patterns in the scanning electron microscope (SEM). An important fundamental question concerns the scattering-angle dependent electron energy distribution, which is relevant for the formation of the Kikuchi diffraction patterns. Here we review the existing experimental data and explore the effective energy spectrum that is operative in the generation of backscatter Kikuchi patterns from silicon. We use a full pattern comparison of experimental data with dynamical electron diffraction simulations. Our energy-dependent cross-correlation based pattern matching approach establishes improved constraints on the effective Kikuchi pattern energy spectrum, which is relevant for high-resolution EBSD pattern simulations and their applications. KW - EBSD KW - Kikuchi pattern KW - Simulation KW - Energy distribution KW - Electron energy PY - 2019 SN - 2469-9950 SN - 2469-9969 VL - 99 IS - 6 SP - 064115-1 EP - 064115-13 PB - AIP AN - OPUS4-47635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Unger, Wolfgang A1 - Böllinghaus, Thomas T1 - Comprehensive study of deuterium-induced effects in in austenitic stainless steel AISI 304L N2 - The damaging impact of hydrogen on the austenitic stainless steel AISI 304 L was analysed. To this aim, samples were charged electrochemically with the hydrogen isotope deuterium (2H, D) and examined with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electron backscatter diffraction (EBSD). The fusion of the obtained chemical and structural information revealed local enrichment of deuterium in austenite, transformation into martensite, crack formation and severe roughening of the specimen surface. The results indicated that martensite was not only formed during charging but also during Desorption and ToF-SIMS examinations. Furthermore, cross-sections of deuterium-charged samples revealed that in preferred deformation bands a g/ε/a 0 evolution is taking place. By means of microscopic analyses and carrier gas hot extraction (CGHE), it was found that the use of NaAsO2 as recombination poison decreased the uptake of hydrogen significantly and resulted in severe precipitation on the specimen surfaces. This is in contrast to the popular presumption that NaAsO2 enhances the uptake of hydrogen (and deuterium) during electrochemical charging by hampering its recombination from Atoms to molecules. KW - AISI 304L KW - Hydrogen KW - ToF-SIMS KW - Deuterium KW - Martensite PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477540 DO - https://doi.org/10.1016/j.ijhydene.2019.03.058 SN - 0360-3199 SN - 1879-3487 VL - 44 IS - 23 SP - 12228 EP - 12238 PB - Elsevier Ltd. AN - OPUS4-47754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Sojref, Regine A1 - Saliwan Neumann, Romeo T1 - Microstructure of bare and sol-gel alumina-coated nickel-base alloy Inconel 625 after long-term oxidation at 900 °C N2 - Though Ni-base superalloys show a high oxidation and corrosion resistance, coatings could still improve these properties, especially if used at temperatures up to 1000 °C. Here, a coating was prepared by applying a boehmite-sol via dip-coating and a subsequent heat treatment at 600 °C for 30 minutes. To evaluate the coating, the oxidation behavior of bare and alumina coated Ni-base alloy Inconel 625 in air at 900 °C was studied for up to 2000 h. Electron microscopic studies of sample surfaces and cross-sections showed that (i) in the 3.5 µm – 6.3 mm thick scale formed on the bare alloy, Fe and Ni are located as fine precipitates at the grain boundaries of the chromia-rich scale, (ii) Ni and Ti are concentrated to a minor degree at the grain boundaries of the scale, too; and for the coated sample: (iii) the only 1.8 µm thick sol-gel alumina coating slows down the formation of chromia on the alloy surface and reduces the outward diffusion of the alloy constituents. The protective effect of the coating was evidenced by (i) diminished chromium diffusion at grain boundaries resulting in less pronounced string-like protrusions at the outer surface of the coated IN 625, (ii) formation of a Cr-enriched zone above the alloy surface which was thinner than the scale on the uncoated sample, (iii) no detectable Cr-depleted zone at the alloy surface, and (iv) a narrower zone of formation of Kirkendall pores. KW - Inconel 625 KW - High-temperature oxidation KW - Oxidation protection KW - Sol-gel coating PY - 2019 DO - https://doi.org/10.1007/s11085-019-09888-z SN - 0030-770X VL - 91 IS - 3-4 SP - 395 EP - 416 PB - Springer Science+Business Media AN - OPUS4-47665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. G. A1 - Agudo Jácome, Leonardo T1 - Thermodynamic study of a refractory complex concentrated alloy (rCCA) using the CALPHAD method N2 - Multi-principal-element alloys (MPEAs), have recently come to the attention of the scientific community due to their potential for improving properties such as, e.g. mechanical strength and oxidation resistance in high temperature structural applications. The AlMo0.5NbTa0.5TiZr refractory (r)CCA is one such candidate, showing a two-phase microstructure after a two-stage heat treatment under argon atmosphere at a controlled cooling rate. Since the application conditions intended for this alloy require a long-term high temperature (> 700 °C) mechanical and oxidation resistance, it becomes necessary to assess the possible phase development in this regime. The diagrams reveal that two BCC-based phases could form during alloy solidification, where one phase would be enriched with Mo, Nb and Ta while the other phase, with Al, Ti and Zr. Activity oxides diagrams show that a stable form of aluminum oxide (α-Al2O3, Pearson symbol: hR10, corundum) can be formed. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - Chemically Complex Alloy KW - CALPHAD KW - Electromicroscopy PY - 2019 AN - OPUS4-50730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koclega, Damian A1 - Radziszewska, A. A1 - Dymek, S. A1 - Kranzmann, Axel T1 - Corrosion behaviour of Ni-Cr-Mo-W coatings in environments containing sulfur N2 - The ferritic steel 13CrMo4-5 due to good properties with relation to attractive price is frequently use in power plants industry. According EN10028-2 this steel can be used up to 570 °C because of its creep behavior but its corrosion resistance limits the use frequently to lower temperatures, depending on gas temperature and slag formation. The corrosion test were performed in environment containing mixture of gases like: O2, COx, SOx and ashes, with elements e.g. Na, Cl, Ca, Si, C, Fe, Al. Exposure time was respectively 240 h, 1000 h and 4500 h in temperature 600 °C. The oxide scale on the 13CrMo4-5 steel was significant thicker than for In686 coating and the difference increase according for longer exposure time. The microstructure, chemical and phase composition of the oxide scales were investigated by means of a light microscope, the electron scanning and transmission microscopes (SEM,TEM) equipped with the EDS detectors. T2 - Gordon Research Conference CY - New London, New Hampshire, USA DA - 21.07.2019 KW - High temperature KW - Corrosion resistance KW - Laser cladding KW - Inconel 686 KW - Aggressive environment PY - 2019 AN - OPUS4-49358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sommer, Konstantin A1 - Bettge, Dirk A1 - Nolze, Gert T1 - Microstructure analysis in AM 316L N2 - Additive manufacturing (AM) offers diverse advantages compared to conventional manufacturing. In this work the microstructure of austenitic steel 316L, manufactured with Selective Laser Melting (SLM), was analyzed and compared to microstructure of 316L hot rolled material. Methods used for analysis are microprobe, optical microscopy and electron backscatter diffraction. T2 - BAM workshop on Additive Manufacturing CY - Berlin, Germany DA - 13.05.2019 KW - 316L KW - selective laser melting KW - microstructure analysis PY - 2019 AN - OPUS4-49880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sommer, Konstantin A1 - Bettge, Dirk A1 - Nolze, Gert T1 - Microstructure Characterization of Additively Manufactured Austenitic Steel 316L N2 - Additive manufacturing processes (AM) offer different advantages compared to conventional manufacturing processes. In this work the microstructure of austenitic steel 316L, manufactured with Selective Laser Melting (SLM), and the powder, used for the process, were investigated. T2 - BAM workshop on Additive Manufacturing CY - Berlin, Germany DA - 13.05.2019 KW - 316L KW - Selective laser melting KW - Microstructure analysis KW - Metal powder characterization PY - 2019 AN - OPUS4-49884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kranzmann, Axel A1 - Midtlyng, Jan A1 - Schlitte, I.-V. A1 - Escoda de Pablo, S. T1 - Corrosion of VM12 SHC in Salt melt N2 - Alkali and alkaline earth chlorides are discussed as heat storage media and are characterized by their low price and high availability. Disadvantages are a high corrosion rate and formation of Cr6+ ions in the melt, as observed in various binary chlorine salt melts. In our work the system NaCl-KCl-MgCl2 is considered. The storage capacity in this salt system is between 2 and 3 MWh per 10 t salt, depending on composition, melting temperature and working temperature. At the same time the system offers a eutectic line, which allows a high variance of the composition and possibly different corrosion rates can be observed. Corrosion tests in melts were carried out and the corrosion layers investigated. The tests with chloride melts on 12% Cr steel show an inner corrosion zone of up to 40 µm depth after 96 hours. The corrosion mechanisms and potential solutions are discussed. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Salt melt KW - Corrosion KW - VM12 SHC PY - 2019 AN - OPUS4-50759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - Probenpräparation für AFM-basierte Untersuchungsverfahren N2 - Adapted and advanced sample preparation of semiconductor layer systems with the focused ion beam for AFM-based test methods N2 - Der vorliegende Vortrag gibt einen Überblick über Probenpräparationen mit der Focused Ion Beam (FIB) für AFM-basierte Untersuchungsverfahren. Anhand zweier Beispiele wird gezeigt, wie ionenstrahlpolierte Lamellen aus Halbleiter-Schichtsystemen elektrisch leitfähig auf Substrate platziert werden, so dass in-situ und in-operando Messungen mit Scanning Microwave Microscope (SMM) bzw. Spectroscopic infrared scanning near-field optical microscope (IR-SNOM) durchgeführt werden können. T2 - 15. Berlin-Brandenburger Präparatorentreffen CY - Potsdam/Golm, Germany DA - 11.04.2019 KW - Focused Ion Beam KW - AFM based test methods KW - Sample preparation KW - Semiconductor materials KW - Layer system PY - 2019 AN - OPUS4-47784 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Kratzig, Andreas A1 - Bettge, Dirk A1 - Knauer, S. T1 - Factors Influencing Droplet Corrosion in Dense Phase CO2 N2 - This work examined the factors that influence the droplet corrosion of CO2 pipeline steels caused by oxyfuel flue gases in dense phase CO2 at 278 K, simulating the underground transport conditions. The wetting properties were studied by contact angle measurement, revealing pH and time dependency on the reactive wetting behaviors of carbon steel X70. Exposure tests with CO2 saturated water droplet on steel surface showed that the impurities (220 ppmv SO2 and 6700 ppmv O2) diffused into the droplet and then reacted with metal surfaces in dense phase condition, forming the corrosion products. The corrosion rate was confirmed strongly depending on the droplet volume as well as the SO2 concentration. Condensation experiments carried out on freshly polished coupons in CO2 with 200 ppmv H2O, 220 ppmv SO2 and 6700 ppmv O2, showed that the formation and aggregation of droplets is time and temperature dependent. At 278 K, condensation happened stronger and the corrosion products, mainly consisted of dense hydrated FeSO3/FeSO4. While at 288 K, more fluffy corrosion products consisting of iron oxide/hydroxide and hydrated FeSO3/FeSO4 were found. Further exposure tests on carbon steel coupons with different surface roughness did not reveal the difference in weight loss/gain and therefore the corrosion rate. T2 - NACE International Corrosion Conference 2019 CY - Nashville, TN, USA DA - 24.03.2019 KW - Carbon Capture, Utilization and Storage (CCUS) KW - Supercritical/dense phase CO2 KW - Carbon steel KW - Droplet corrosion KW - Condensation PY - 2019 AN - OPUS4-47916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Yevtushenko, Oleksandra A1 - Bettge, Dirk T1 - Corrosion Aspects for Materials to be Used in CC(U)S Applications N2 - This contribution provides current findings regarding materials susceptibility for carbon capture, utilization and storage (CCUS) applications. Basing on results gathered in 2 German long-term projects (COORAL and CLUSTER) suitable materials are introduced as well as dominating impurities of the CO2-stream and corrosion mechanisms. Investigations cover the whole CCUS process chain and provide material recommendations for certain parts. T2 - 1st International Conference on Corrosion Protection and Application CY - Chongqing, China DA - 09.09.2019 KW - Carbon KW - Capture KW - Storage KW - Utilization KW - CCS KW - CCU KW - CO2 KW - Corrosion PY - 2019 AN - OPUS4-49302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Roohbakhshan, Farshad A1 - Nolze, Gert A1 - Fedelich, Bernard A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic Operation Performance of 9-12% Cr Ferritic-Martensitic Steels. Part 2: Microstructural Evolution during Cyclic Loading and its Representation in a Physically-based Micromechanical Model N2 - The current trend towards cyclic, “flexible” operation of fossil-fueled power plants constitutes a major issue regarding lifetime and operational safety of the respective installations and their components, as was outlined in our complementary contribution (Part 1). The present contribution reports on the investigation of the microstructure evolution in cyclically loaded ferritic-martensitic steels and its representation in a physically-based micromechanical model. For this purpose, specimens of P92 steel grade from the mechanical test programme outlined in our companion contribution (Part 1) were analyzed by scanning electron microscopy (SEM), including backscattered diffraction (EBSD) mapping, and transmission electron microscopy (TEM). A novel method was implemented to improve angular resolution of EBSD scans. Additionally, a correlative microscopy approach was developed and used to correlate EBSD and TEM measurements on the same locations of thick regions of electron transparent specimens. By applying these techniques, a detailed quantitative microstructure description of the as-received material condition, namely in terms of subgrain morphology and dislocation density/distributions, was established. Comparisons of as-received and cyclically loaded conditions from tests interrupted at different stages of lifetime indicate a rapid redistribution of in-grain dislocations with a strong interaction between mobile dislocations and low angle grain boundaries (LABs). The proposed micromechanical model is formulated in a viscoplastic self-consistent (VPSC) scheme, which is a mean-field approach that allows us to include the crystal details at the level of slip systems while avoiding the considerable computational costs of full-field approaches (such as the classical crystal plasticity finite element analysis). Being physically-based, the model uses dislocation densities and includes the interaction between dislocations, e.g. annihilation of mobile dislocations, and evolution of microstructure, e.g. the grain coarsening. Particularly, the constitutive laws for dislocation evolution and interaction between dislocations and low angle boundaries are calibrated based on two-dimensional discrete dislocation dynamic (2D DDD) simulations, which are performed at a micro-/meso-scale. The results of the beforementioned EBSD experiments are considered as a direct input, involving e.g. the amount of geometrically necessary dislocations, average misorientations and grain characteristics. T2 - 45th MPA-Seminar 2019 CY - Leinfelden-Echterdingen, Germany DA - 01.10.2019 KW - Tempered martensite ferritic steel KW - Dislocation KW - Electron backscattered diffraction (EBSD) KW - Transmission electron microscopy (TEM) KW - Microstructure KW - Physically based material model PY - 2019 AN - OPUS4-49346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Falkenhagen, Jana A1 - Becker, Roland A1 - Hoffmann, Katrin A1 - Resch-Genger, Ute A1 - Tschiche, Harald A1 - Reinsch, Stefan A1 - Weidner, Steffen ED - Scholz, Philipp T1 - Analytical toolset to characterize polyurethanes after exposure to artificial weathering under systematically varied moisture conditions N2 - Polyether and -ester urethanes (PU) were exposed to artificial weathering at 40 °C and artificial UV radiation in a weathering chamber. In 3 parallel exposures, humidity was varied between dry, humid, and wet conditions. Material alteration was investigated by various analytical techniques like size exclusion chromatography (SEC), liquid chromatography-infrared spectroscopy (LC-FTIR), thermal-desorption gas chromatography-mass spectrometry (TD-GC-MS), fluorescence mapping and dynamic mechanical analysis (DMA). Our results show that depending on the weathering conditions, different degradation effects can be observed. By means of SEC an initial strong decrease of the molar masses and a broadening of the mass distributions was found. After a material dependent time span this was followed by a plateau where molar mass changes were less significant. A minor moisture-dependent degradation effect was only found for polyester PU. Fluorescence measurements on two materials revealed an increase in the luminescence intensity upon weathering process reaching a saturation level after about 500 h. The changes in the optical properties observed after different exposure conditions and times were very similar. The TD-GC-MS data showed the fate of the stabilizers and antioxidant in the course of weathering. LC-FTIR measurements revealed a change in peak intensities and the ratio of urethane and carbonyl bands. KW - Polyurethane KW - Artificial weathering KW - Moisture KW - Crosslinking KW - Degradation PY - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0142941819303708 DO - https://doi.org/10.1016/j.polymertesting.2019.105996 SN - 0142-9418 VL - 78 SP - 105996, 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-48625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Humphrey, J.K. A1 - Gibson, A.G. A1 - Hörold, Andreas A1 - Trappe, Volker A1 - Gettwert, V. T1 - Assessing the structural integrity of carbon-fibre sandwich panels in fire: Bench-scale approach N2 - The fire resistance of lightweight sandwich panels (SW) with carbon fibre/epoxy skins and a poly(methacryl imide) (PMI) foam core is investigated in compression under direct application of a severe flame (heat flux=200 kW m−2). A bench-scale test procedure was used, with the sample held vertically. The epoxy decomposition temperature was quickly exceeded, with rapid flash-over and progressive core softening and decomposition. There is a change in failure mode depending on whether the load is greater or less than 50% of the unexposed failure load, or in other words if one or two skins carry the load. At high loads, failure involved both skins with a single clear linear separation across each face. There is an inflection in the failure time relationship in the ∼50% load region, corresponding to the time taken for heat to be transmitted to the rear face, along with a change in the rear skin failure mode from separation to the formation of a plastic hinge. The integrity of the carbon front face, even with the resin burnt out, and the low thermal diffusivity of the core, both play key roles in prolonging rear face integrity, something to be borne in mind for future panel design. Intumescent coatings prolong the period before failure occurs. The ratio of times to failure with and without protection is proposed as a measure of their effectiveness. Apart from insulation properties, their adhesion and stability under severe fire impact play a key role. KW - Carbon fibres KW - Sandwich KW - Structural composites KW - Fracture KW - High-temperature properties KW - Surface treatments PY - 2019 DO - https://doi.org/10.1016/j.compositesb.2018.11.077 SN - 1359-8368 VL - 164 SP - 82 EP - 89 PB - Elsevier AN - OPUS4-46908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baesso, Ilaria A1 - Altenburg, Simon A1 - Günster, Jens T1 - Co-axial online monitoring of Laser Beam Melting (LBM) N2 - Within the perspective of increasing reliability of AM processes, real-time monitoring allows part inspection while it is built and simultaneous defect detection. Further developments of real-time monitoring can also bring to self-regulating process controls. Key points to reach such a goal are the extensive research and knowledge of correlations between sensor signals and their causes in the process. T2 - BAM workshop on Additive Manufacturing CY - BAM, Berlin, Germany DA - 13.05.2019 KW - Laser Beam Melting KW - Process Monitoring KW - Co-axial monitoring KW - 3D imaging PY - 2019 AN - OPUS4-48517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghasem Zadeh Khorasani, Media A1 - Elert, Anna Maria A1 - Hodoroaba, Vasile-Dan A1 - Agudo Jácome, Leonardo A1 - Altmann, Korinna A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Short- and long-range mechanical and chemical interphases caused by interaction of Boehmite (γ-AlOOH) with anhydride-cured epoxy resins N2 - Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands. KW - Nanocomposites KW - Interphase KW - Intermodulation AFM KW - Electron microscopy KW - Infrared nano AFM PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483672 UR - https://www.mdpi.com/2079-4991/9/6/853/htm DO - https://doi.org/10.3390/nano9060853 SN - 2079-4991 VL - 9 IS - 6 SP - 853, 1 EP - 20 PB - MDPI AN - OPUS4-48367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Schönauer-Kamin, D. A1 - Moos, R. A1 - Giovanelli, F. A1 - Rabe, Torsten T1 - Influence of pressure assisted sintering and reaction sintering on microstructure and thermoelectric properties of bi-doped and undoped calcium cobaltite N2 - Calcium cobaltite (Ca3Co4O9) is considered as one of the most promising thermoelectric p-type oxides for energy harvesting applications at temperatures above 500 °C. It is challenging to sinter this material as its stability is limited to 920 °C. To facilitate a practicable and scalable production of Ca3Co4O9 for multilayer generators, a systematic study of the influence of powder calcination, Bi-doping, reaction sintering, and pressure-assisted sintering (PAS) on microstructure and thermoelectric properties is presented. Batches of doped, undoped, calcined, and not calcined powders were prepared, tape-cast, and sintered with and without uniaxial pressure at 900 °C. The resulting phase compositions, microstructures and thermoelectric properties were analysed. It is shown that the beneficial effect of Bi-doping observed on pressureless sintered samples cannot be transferred to PAS. Liquid phase formation induces distortions and abnormal grain growth. Although the Seebeck coefficient is increased to 139 µV/K by Bi-doping, the power factor is low due to poor electrical conductivity. The best results were achieved by PAS of calcined powder. The dense and textured microstructure exhibits a high power factor of 326 µW/mK² at 800 °C but adversely high thermal conductivity in the relevant direction. The figure of merit is higher than 0.08 at 700 °C. KW - Ceramics KW - Calcium cobaltite KW - Thermoelectric properties KW - Calcination KW - Pressure-assisted sintering PY - 2019 DO - https://doi.org/10.1063/1.5107476 SN - 0021-8979 VL - 126 IS - 7 SP - 075102-1 EP - 075102-11 PB - AIP Publishing CY - Melville AN - OPUS4-48708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick A1 - Mieller, Björn A1 - Rabe, Torsten T1 - Small batch preparation of ready-to-press powder for systematic studies N2 - Efficient studies of scarce or expensive materials require material saving processes. Therefore, a high yield concept for small batch preparation of ready-to-press powder is exemplarily presented for yttria stabilized nano-zirconia (d50 < 50 nm). The concept involves small batch preparation in an ultrasound resonator, dispersant selection based on zeta potential measurements, evaluation of slurry stability using an analytical centrifuge, and preparation of ready-to-press powder by freeze drying. Freeze drying offers key advantages. Process efficiency and high yield above 95 % are independent of sample size. The dried product does not require further mechanical treatment like milling or grinding. Side effects like migration of additives are avoided. An optimized freeze drying process tolerates slurries with moderate stability. Thus, efforts for slurry development can be reduced. Generally, identifying a suitable dispersing agent requires only 3-5 zeta potential measurements. Slurry stability is rechecked using an analytical centrifuge, which also accounts for steric stabilization. An ultrasound resonator is used to disperse the powder without contamination, which becomes critical for small batches. The described route is exemplarily presented for the development of an additive recipe for nano-sized zirconia powder, targeting for good pressing behavior and high green density. Therefore, a variety of binding and lubricating agents were tested. Following the presented route, 80 g zirconia powder were sufficient to conduct a study including slurry development and five sample sets with varying composition, each set comprising five discs (d = 20 mm and h = 2 mm). T2 - 94. DKG Jahrestagung CY - Leoben, Austria DA - 05.05.2019 KW - Fine Powder KW - Slurry KW - Freeze Drying PY - 2019 AN - OPUS4-48293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geyler, Paul A1 - Rabe, Torsten A1 - Mieller, Björn A1 - Léonard, Fabien T1 - Machine learning assisted evaluation of the shape of VIAs in a LTCC multilayer N2 - The introduction of the 5G technology and automotive radar applications moving into higher frequency ranges trigger further miniaturization of LTCC technology (low temperature co-fired ceramics). To assess dimensional tolerances of inner metal structures of an industrially produced LTCC multilayer, computer tomography (CT) scans were evaluated by machine learning segmentation. The tested multilayer consists of several layers of a glass ceramic substrate with low resistance silver-based vertical interconnect access (VIA). The VIAs are punched into the LTCC green tape and then filled with silver-based pastes before stacking and sintering. These geometries must abide by strict tolerance requirements to ensure the high frequency properties. This poster presents a method to extract shape and size specific data from these VIAs. For this purpose, 4 measurements, each containing 3 to 4 samples, were segmented using the trainable WEKA segmentation, a non-commercial machine learning tool. The dimensional stability of the VIA can be evaluated regarding the edge-displacement as well as the cross-sectional area. Deviation from the ideal tubular shape is best measured by aspect ratio of each individual layer. The herein described method allows for a fast and semi-automatic analysis of considerable amount of structural data. This data can then be quantified by shape descriptors to illustrate 3-dimensional information in a concise manner. Inter alia, a 45 % periodical change of cross-sectional area is demonstrated. T2 - DKG Jahrestagung 2019 CY - Leoben, Austria DA - 06.05.2019 KW - Machine Learning KW - LTCC multilayer KW - 5G PY - 2019 AN - OPUS4-48289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Electrode area dependence of dielectric breakdown strength N2 - Dielectric breakdown of ceramics is widely believed to originate from microstructural defects. Still, there is no commonly accepted model for the origin and process of dielectric failure that covers all observed phenomena and dependencies. In analogy to mechanical strength, the Weibull distribution is commonly used to evaluate dielectric strength data. This works well for a given group of specimens with constant geometry. But unlike mechanical strength, dielectric strength scales with the inverse square root of sample thickness. This cannot be explained by the classic Weibull concept. The Griffith type energy release rate model of dielectric breakdown proposed by Schneider is based on space charge injection and conducting filaments from the sample surface. This model incorporates the distinct thickness dependence and the pronounced influence of surface defects. Based on this model and the classic Weibull probability of failure, Schneider’s group theoretically derived a probability of breakdown that predicts an increase of failure probability with increasing electrode area. In our study we tested this model with dielectric strength data measured on dense alumina samples using different electrode areas. Weibull modulus and characteristic dielectric strength (scale parameter) were determined for a set of measurements using small electrodes. These values were used to calculate the failure probability under large electrodes according to the model. The calculated data excellently fits the measured values. Thus, our experiments substantiate the assumptions made in the breakdown model and the significance of surface defects for dielectric failure. T2 - 94. DKG Jahrestagung CY - Leoben, Austria DA - 05.05.2019 KW - Dielectric strength KW - Breakdown strength KW - Ceramics PY - 2019 AN - OPUS4-48015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Evaluation of a multi-purpose measurement cell for standardized volume resistivity measurements at high temperatures N2 - The ProboStat is a multi-purpose measurement cell suitable for various electrical and physical measurements under different atmospheres and at high temperatures. Disc and bar shaped samples are sandwiched between platinum electrodes at the top of the tubular cell. The gas tight assembly can be inserted into a furnace. Different gases can be flushed through the tube. For this study, a ProboStat was adapted to measure volume resistivity of ceramic insulators at high temperatures according to standards. The standardized measurement of volume resistivity of ceramic insulators requires the consideration of many specifications including sample diameter, thickness, electrode design, and the proportion of these characteristics. Measurements are ideally performed in a state of dielectric equilibrium. The time-related slope of resistivity of a specific sample follows a power function. Thus, care must be taken when choosing a charge time or defining the duration of a measurement. As fringing of the guarded electrode occurs under high voltage, the effective electrode area for evaluation of the results should be corrected with respect to sample thickness and electrode design. The demands of effective standards on sample geometry and electrode design are stricter for room temperature measurements than for high temperature measurements. To perform high temperature measurements on ceramic samples that also fulfill the demands on room temperature measurements, a ProboStat was equipped with a dedicated large sample setup for discs with diameters of up to 60 mm. The volume resistivity of different alumina samples was first measured at room temperature in a standard test fixture and then compared to results obtained with the ProboStat. All measurements were performed for at least 100 min using a 26 mm guarded electrode. High temperature measurements at 500 °C were performed using the same samples. Room temperature values obtained with the standard test fixture are in the order of 10^17 Ohm·cm. The quantitative effect of electrode area correction is presented. Practical issues related to the use of the multi-purpose cell are addressed. These include electrode material selection, application of electrodes, and compensation of leakage currents. High temperature results of volume resistivity of the different alumina samples are presented. The validity is discussed with respect to the suitability of the multi-purpose cell for such measurements. T2 - XVI Conference and Exhibition of the European Ceramic Society (ECerS 2019) CY - Torino, Italy DA - 16.06.2019 KW - ceramics KW - alumina KW - volume resistivity PY - 2019 AN - OPUS4-48270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weber, Kathrin A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Stephan-Scherb, Christiane T1 - A µ‐XANES study of the combined oxidation/sulfidation of Fe–Cr model alloys N2 - The precise analysis of cation diffusion profiles through corrosion scales is an important aspect to evaluate corrosion phenomena under multicomponent chemical load, as during high‐temperature corrosion under deposits and salts. The present study shows a comprehensive analysis of cation diffusion profiles by electron microprobe analysis and microbeam X‐ray absorption near edge structure (µ‐XANES) spectroscopy in mixed oxide/sulfide scales grown on Fe–Cr model alloys after exposing them to 0.5% SO2. The results presented here correspond to depth‐dependent phase identification of oxides and sulfides in the corrosion scales by µ‐XANES and the description of oxidation‐state‐dependent diffusion profiles. Scales grown on low‐ and high‐alloyed materials show both a well‐pronounced diffusion profile with a high concentration of Fe3+ at the gas and a high concentration of Fe2+ at the alloy interface. The distribution of the cations within a close‐packed oxide lattice is strongly influencing the lattice diffusion phenomena due to their different oxidation states and therefore different crystal‐field preference energies. This issue is discussed based on the results obtained by µ‐XANES analysis. KW - X-ray absorption spectroscopy KW - Oxidation KW - Sulfidation PY - 2019 DO - https://doi.org/10.1002/maco.201810644 VL - 70 IS - 8 SP - 1360 EP - 1370 PB - Wiley VCH-Verlag AN - OPUS4-47934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Sonntag, Nadja A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic operation performance of 9-12% Cr ferritic-martensitic steels part 1: Cyclic mechanical behavior under fatigue and creep-fatigue loading N2 - The current competitive situation on electricity markets forces power plants into cyclic operation regimes with frequent load shifts and starts/shutdowns. In the present work, the cyclic mechanical behavior of ferritic-martensitic 9-12 % Cr steels under isothermal and thermomechanical loading was investigated for the example of grade P92 material. A continuous softening was observed under all loading conditions. The introduction of hold periods to the applied cycles reduced material lifetime, with most prominent effects at technologically relevant small strain levels. The microstructural characterization reveals a coarsening of the original “martensitic” lath-type microstructure to a structure with polygonal subgrains and reduced dislocation density. The microstructural data forms the input for a physically-based modelling approach, both of which are presented in “Part 2: Microstructural Evolution during Cyclic Loading and its Representation in a Physically-based Micromechanical Model“. T2 - 45. MPA-Seminar CY - Leinfelden-Echterdingen, Germany DA - 01.10.2019 KW - Tempered Martensite Ferritic Steels KW - P92 KW - Low Cycle Fatigue KW - Thermo-Mechanical Fatigue KW - Creep-Fatigue PY - 2019 SP - 75 EP - 79 PB - MPA (Materialprüfungsanstalt Universität Stuttgart) CY - Stuttgart AN - OPUS4-50051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Mohr, Gunther A1 - Hilgenberg, Kai A1 - Straße, Anne A1 - Gumenyuk, Andrey A1 - Winterkorn, René A1 - Pittner, Andreas A1 - Sommer, Konstantin A1 - Bettge, Dirk A1 - Kranzmann, Axel A1 - Nolze, Gert A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Charmi, Amir A1 - Falkenberg, Rainer A1 - Skrotzki, Birgit A1 - Werner, Tiago A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Ulbricht, Alexander A1 - Sprengel, Maximilian A1 - Kromm, Arne A1 - Thiede, Tobias A1 - Bruno, Giovanni T1 - Ageing in additively manufactured metallic components: from powder to mechanical failure” an overview of the project agil N2 - An overview of the BAM funed Focus Area Materials Project "AGIL" will be presented. AGIL focussed on the stdiy of the ageing characteristics of additively manufactured austenitic stainless steel with a "powder to mechanical failure" Approach. Recent Highlights are presented and a perspective for future studies. T2 - Workshop on Additive Manufacturing CY - BAM, Berlin, Germany DA - 13.05.2019 KW - Residual stress KW - Additive Manufacturing KW - Non-destructive testing KW - Microstructure characterisation KW - Tensile testing KW - Fatigue KW - Crystal Plasticity Modelling KW - Crack propagation PY - 2019 AN - OPUS4-49823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Jürgens, Maria A1 - Sonntag, Nadja A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic operation performance of 9 -12% cr ferritic martensitic steels part 1: cyclic mechanical behavior under fatigue and creep fatigue loading N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in fossil fueled power plants due to their excellent creep and oxidation resistance, but changes in electricity markets during the last two decades have considerably changed the typical working conditions of these facilities. The growing share of renewable energy sources in power generation forces most of these plants into flexible operation with frequent load shifts or shutdowns. These cyclic operation profiles constitute a major lifetime issue, raising the question which fundamental processes govern the reaction of ferritic-martensitic steels to cyclic load and temperature variations. The present contribution reports on current findings obtained in a multidisciplinary project funded by German Ministry of Education and Research (BMBF) which combines cyclic mechanical and cyclic oxidation testing of different 9-12% Cr grades with detailed microstructural analyses and related micromechanical modeling. In the present first part of our contribution, an overview will be given on the results obtained in the mechanical testing programme of the project. Mechanical analyses were carried out on P91 and (mainly) P92 steel grades, particularly looking at softening phenomena and lifetimes obtained in isothermal cyclic loading (low cycle fatigue, LCF), non-isothermal cyclic loading (thermo-mechanical fatigue, TMF), and service-like combinations of creep and fatigue periods. For this purpose, cylindrical specimens were extracted from thick-walled steam pipes, orthogonal to the pipe axis, and subjected to strain controlled cyclic loading (± 0.2 to ±0.5 % mechanical strain) to different degrees of softening at temperatures up to 620 °C. The test results will be presented and discussed with a focus on the impact of hold periods (i.e. combined creep-fatigue conditions) on mechanical softening, lifetime and crack formation. Details on the microstructural evolution and their representation in a micromechanical model will be given in a second, complementary contribution to this conference. T2 - 45. MPA-Seminar CY - Stuttgart, Germany DA - 01.10.2019 KW - Tempered Martensite Ferritic Steels KW - Low Cycle Fatigue KW - Creep-Fatigue KW - Thermo-Mechanical Fatigue KW - P92 PY - 2019 AN - OPUS4-50050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -