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 - 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 - 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 - 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 - 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 - 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 - RPRT A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Salehi, M. T1 - Alterungsbeständige keramische Federsensoren durch nanostrukturierte Werkstoffe, Präzisionsbearbeitung und hochdielektrische Nanosuspensionen N2 - Das Ziel des Gesamtvorhabens bestand darin, einen neuartigen kapazitiven Sensortyp zur hochauflösenden Bestimmung von Masse- und Gravitationskraftänderungen zu entwickeln. Bisherige Technologien nutzten dafür Federn oder Biegebalken aus gehärteten metallischen Werkstoffen, deren Alterungsverhalten die Präzision der Kräftemessung begrenzen. Grundprinzip des neuen Sensortyps ist es, eine auf die keramische Feder einwirkenden Änderung der Gewichts- oder Gravitationskraft durch eine Erfassung der Kapazitätsänderung am Sensor zu bestimmen. Dazu muss die durch Stauchung oder Dehnung der Feder entstehende Kapazitätsänderung mit hoher Auflösung reproduzierbar gemessen werden. Neben einem geeigneten Sensordesign waren Lösungen für Messsignalerfassung und -auswertung (Elektronik/Software) und die Systemintegration zu entwickeln. Die wichtigsten im Rahmen des BAM-Teilvorhabens erzielten Ergebnisse sind: - Ausgehend von kommerziellen High-end Keramikpulvern wurden durch Optimierung der keramischen Technologie nahezu porenfreie Al2O3, ZrO2 und Si3N4-Werkstoffe hergestellt und bezüglich Gefüge und Phasenbestand sowie mechanischen, thermischen und elektrischen Eigenschaften bewertet. Insbesondere die defektfreie Herstellung von nanostrukturierten Werkstoffen erforderte umfangreiche Variationen der Prozessparameter. Geeignete Werkstoffvarianten wurden für die Federherstellung ausgewählt. - Gemeinsam mit den Projektpartnern wurden Layoutvarianten für Schraubendruckfedern mit rechteckigem Windungsquerschnitt und für die Federeinbindung in das Sensorsystem erarbeitet. - 4 Federvarianten wurden an der BAM durch Hartbearbeitung von gesinterten Hohlzylindern umgesetzt. Fertigungstoleranzen von < ±10 µm für Windungsbreite, Windungshöhe und Windungsabstand und dünnfilm-kompatible innere Windungsflächen (Ra < 0,2 µm) wurden erreicht. Al2O3- und ZrO2-Federn können rissfrei und mit sehr guter Kantenqualität gefertigt werden, bei Si3N4-Federn konnten Kantenschädigungen nicht vollständig verhindert werden. - Mit der entwickelten Herstellungstechnologie können sowohl „harte“ als auch sehr „weiche“ Federn produziert werden. Federkonstanten zwischen 0,02 N/mm und 10 N/mm wurden realisiert. Die Reproduzierbarkeit der Federfertigung ist gegeben, innerhalb einer Charge unterschieden sich die Federkonstanten der gefertigten Federn nur um etwa +/- 1%. - An einem speziell entwickelten Versuchsstand wurden die Federn unter zyklischer Druckbelastung im Temperaturbereich von -20 bis +80 °C untersucht. An den Al2O3- und ZrO2-Federn wurden keine Schädigungen beobachtet, die Federkonstante wird durch die zyklische Langzeitbelastung nicht verändert. - Die Eignung der keramischen Federn für den Applikationsfall wurde mit zahlreichen Spannungs-Dehnungs-Experimenten, teilweise an speziell aufgebauten Versuchsapparaturen, untersucht. An Al2O3- und Si3N4-Federn wurde – wie erwartet – gefunden, dass die Federkonstante unabhängig von der Belastungsgeschwindigkeit ist und unter konstanter Last auch über lange Zeiträume keine Verformung auftritt. Überraschenderweise zeigten ZrO2 (TZP)-Federn ein zeitabhängiges Verhalten unter Last. Dieses ist besonders stark bei Y-stabilisierten Werkstoffvarianten ausgebildet, wurde aber mit Hochpräzisionsmessungen auch bei Ce-stabilsierten Werkstoffen nachgewiesen. Die Deformation ist reversibel, eine vollständige Relaxation wird erst nach Tagen erreicht. Aufgrund der zeitabhängigen Verformung können ZrO2 (TZP)-Federn, trotz ihrer hervorragenden Festigkeit und Bruchzähigkeit, nicht für die konzipierten Sensorfedern eingesetzt werden. - Das durch die Fa. Siegert TFT entwickelte Metallisierungs-Schichtsystem, bestehend aus aufgesputterten Ti-, Pt- und Au-Schichten verstärkt durch eine galvanisch aufgebrachte Au-Schicht, wurde an der BAM umfassend bewertet. Die Schichten sind untereinander und mit der Keramik weitgehend defektfrei verbunden, die lokale Schichtdicke schwankt jedoch bedingt durch Abschattungseffekte während der Beschichtungsvorgang. Es wurden Schichtwiderstände zwischen 50 und 90 Ohm und damit die Zielvorgabe des Projektes (< 100 Ohm) erreicht. In statischen und dynamischen Belastungstests wurden keine Veränderungen der Leitungswiderstände festgestellt. - Zur Erhöhung der Kapazität des Kondensators kann der Raum zwischen den Federwindungen statt mit Luft mit einer Flüssigkeit mit hoher Dielektrizitätskonstante gefüllt werden. Als geeignete Flüssigkeit wurde Propylencarbonat mit einer Dielektrizitätskonstante von 65, einem hohen Siedepunkt und einer geringen Viskosität identifiziert. Um eine noch höhere Dielektrizitätskonstante zwischen den Federwindungen zu erreichen. wurden Suspensionen aus Silikonöl und nanokristallinem Bariumtitanat hergestellt und bezüglich ihrer Langzeitstabiltät charakterisiert. - Gemäß den Anforderungen des Projektpartners KOMPASS wurden maßgeschneiderte Al2O3-Federn mit einer Federkonstante < 0,1 N/mm hergestellt und für den Aufbau des finalen Demonstrator eingesetzt. Die prinzipielle Funktionsfähigkeit des neuen Sensorkonzeptes auf Basis keramischer Federn wurde mit dem im Projekt aufgebauten Demonstrator nachgewiesen. Die Umsetzung der F+E-ergebnisse in eine industrielle Nutzung zur Herstellung von Gravimetern wird vom Projektpartner KOMPASS angestrebt und ist bereits mit detaillierten Zeitplänen untersetzt. KW - Langzeitstabilität KW - Sensorik KW - Keramikfeder KW - Spannungs-Dehnungs-Verhalten PY - 2019 UR - https://www.gbv.de/dms/tib-ub-hannover/1681417375.pdf UR - https://www.tib.eu/de/suchen/id/TIBKAT%3A1681417375/Alterungsbest%C3%A4ndige-keramische-Federsensoren-durch/ SP - 1 EP - 64 PB - Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-50742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Grützner, Stefan A1 - Haftaoglu, Cetin A1 - Kindrachuk, Vitaliy A1 - Vöse, Markus T1 - Möglichkeiten und Grenzen der rechnerischen Bewertung der Lebensdauer von Bauteilen unter TMF: Viskoplastische Modelle N2 - In diesem Vortrag wird auf einige noch offene Frage zur Anwendung der viskoplastischen Modellierung bei Hochtemperaturermüdung. Insbesondere auf das Problem der Parameterbestimmung wird eingegangen. T2 - Workshop "Konstitutive Viskoplastische Materialmodelle" CY - Institut für Werkstoffkunde (IfW), Technische Universität Darmstadt, Germany DA - 06.11.2019 KW - TMF KW - Viskoplastisch KW - Modell KW - Hochtemperaturermüdung KW - LCF PY - 2019 AN - OPUS4-49611 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Akatsuka, C. A1 - Honma, T. A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Tanaka, S. A1 - Komatsu, T. T1 - Surface crystallization and gas bubble formation during conventional heat treatment in Na2MnP2O7 glass N2 - The crystallization behavior of sodium ion conductive Na2MnP2O7 glass was examined to clarify the crystallization mechanism. The formation of thermodynamically metastable phase, layered Na2MnP2O7, at the surface of the glass occurred. Heat treatment at 430 °C for 3 h lead to surface crystals of Na2MnP2O7 oriented with the (101) direction perpendicular to the sample surface. As the heat treatment temperature increased, the glass-ceramic samples deformed, and the presence numerous micro bubbles due to dissolved water was detected. KW - Glass-ceramic KW - Crystallization KW - Sodium ion batteries KW - Bubble formation KW - Phosphate PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.01.030 VL - 510 SP - 36 EP - 41 PB - Elsevier B.V. AN - OPUS4-49618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - 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 - 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 - 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 - 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 - 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 - 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 - CONF A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Umgebungsinduzierte Spannungsrissbildung (ESC) von PE-HD induziert durch äußerliche Einwirkung organischer Flüssigkeiten N2 - Polyethylen hoher Dichte (PE-HD) wird als Werkstoff für Rohre und Behälter für den Transport und zur Lagerung von Gefahrgütern verwendet. Für die Beurteilung und technische Freigabe dieser Materialien ist insbesondere das Verständnis des Schädigungsmechanismus des langsamen, umgebungsbedingten Spannungsrisses (engl.: „environmental stress cracking“, ESC) essentiell. ESC tritt bei relativ geringen auf einen Werkstoff einwirkenden mechanischen Spannungen auf. An lokalen Fehlstellen (z.B. Defekte, Inhomogenitäten, Kerben) beginnend wächst ein Riss langsam durch das Material und führt nach gewisser Zeit zu einem charakteristischen, pseudo-spröden Bruch. Dabei wird das Risswachstum durch äußere Medieneinwirkung zusätzlich entscheidend beeinflusst. Dieses langsame Risswachstum wird als Hauptursache für das plötzliche und unerwartete Versagen von Polymerwerkstoffen angesehen. Eine etablierte Prüfmethode zur Bewertung des Materialverhaltens gegenüber dieses Schädigungsmechanismus ist der Full-Notch Creep Test (FNCT), der für PE-HD Behältermaterialien üblicherweise unter Verwendung von wässrigen Netzmittellösungen (Arkopal N 100) durchgeführt wird. Die aus dem FNCT erhaltene Standzeit dient dabei als Bewertungskriterium für verschiedene PE-HD-Werkstoffe. In einer Studie wurden neben einer typischen Arkopal-N-100-Netzmittellösung praktisch relevante, organische Flüssigkeiten wie Biodiesel und Diesel als Testmedien verwendet, um deren Einfluss auf das ESC-Verhalten von PE-HD-Behältermaterialien zu charakterisieren. Neben der klassischen Standzeit-Auswertung erfolgte eine erweiterte Bruchflächenanalyse mittels Licht- (LM), Laserscanning- (LSM) und Rasterelektronenmikroskopie (REM). Insbesondere die LSM erlaubt eine schnelle und einfache Unterscheidung pseudo-spröder und duktiler Bruchbilder, die zur Beurteilung der Repräsentativität des FNCT für das dem Spannungsriss zugrundeliegenden langsamen Risswachstum von Bedeutung ist. T2 - Polymer Service GmbH Merseburg - "Lebensdauerabschätzung von Polymerwerkstoffen - Möglichkeiten und Grenzen" CY - Merseburg, Germany DA - 27.03.2019 KW - Environmental Stress Cracking (ESC) KW - Slow Crack Growth (SCG) KW - Spannungsriss KW - Polyethylen hoher Dichte KW - Full-Notch Creep Test (FNCT) KW - Bruchflächenanalyse KW - Laserscanningmikroskopie (LSM) PY - 2019 AN - OPUS4-52947 LA - deu 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 - Schilling, Markus A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Addressing ESC using FNCT enhanced by optical fracture surface analysis N2 - During their lifetime, polymer components subjected to mechanical loads and environmental influences show a loss of their mechanical properties required for their specific applications. In this respect, the craze-crack damage mechanism slow crack growth (SCG) is relevant for PE-HD components used in high-performance applications such as pipes and containers for the storage and transport of dangerous goods. SCG is considered to be the major failure mechanism in polyolefins and it typically occurs suddenly and unexpectedly. Due to the fields of application, SCG is a safety relevant issue. To test for the resistance of PE-HD pipe and container materials against SCG, the full-notch creep test (FNCT) is widely applied in Europe. In this study, SCG phenomena in PE-HD are investigated in detail based on an improved FNCT, especially including the consideration of the influence of environmental liquids effecting the damage mechanism. Using an enhanced fracture surface and a crack propagation analysis with imaging techniques such as light microscopy (LM), laser scanning microscopy (LSM), X-ray computed tomography (CT-scan) and scanning electron microscopy (SEM), detailed data concerning SCG are obtained. The combined application of FNCT and such imaging techniques is explicitly advantageous and recommended to gain important information on damage occurring to PE-HD induced by mechanical stress and the influence of environmental liquids, which is essential within the Fourth Industry Revolution. T2 - PPS Europe-Africa 2019 Regional Conference (PPS 2019) CY - Pretoria, South Africa DA - 18.11.2019 KW - Polyethylene, PE-HD KW - Full-Notch Creep Test (FNCT) KW - Fracture surface analysis KW - Slow crack growth KW - Environmental stress cracking KW - Laser Scanning Microscopy (LSM) KW - Scanning Electron Microscopy (SEM) PY - 2019 AN - OPUS4-50939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Marschall, Niklas A1 - Niebergall, Ute A1 - Böhning, Martin T1 - An optical criterion for the assessment of Full-Notch Creep Test (FNCT) fracture surfaces N2 - The full-notch creep test (FNCT) is a common method to evaluate the environmental stress cracking (ESC) behavior of high-density polyethylene (PE-HD) container materials . The test procedure as specified in ISO 16770 provides a comparative measure of the resistance against ESC using the time to failure of specimens mechanically loaded in a well-defined liquid environment. Since the craze-crack damage mechanism underlying the ESC process is associated with brittle failure, the occurrence of globally brittle fracture surfaces is a prerequisite to consider an FNCT measurement as representative for ESC . Therefore, an optical evaluation of FNCT fracture surfaces concerning their brittleness is essential. Due to the experimental setup, an inevitable increase of the true mechanical stress and the associated appearance of small ductile parts on fracture surfaces is induced in any case. Hence, an FNCT experiment is considered as 'valid', if the corresponding fracture surface is predominantly brittle . Based on laser scanning microscopy (LSM) height data of FNCT fracture surfaces , a universal and easy-to-use phenomenological criterion was developed to assess the validity of distinct FNCT experiments. This criterion is supposed to facilitate a quick evaluation of FNCT results in practical routine testing. T2 - PPS Europe-Africa 2019 Regional Conference (PPS 2019) CY - Pretoria, South Africa DA - 18.11.2019 KW - Full-Notch Creep Test (FNCT) KW - Polyethylene, PE-HD KW - Fracture surface analysis KW - Environmental stress cracking (ESC) KW - Optical criterion KW - Brittle fracture PY - 2019 AN - OPUS4-50940 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - CONF A1 - Behrens, H. A1 - Balzer, R. A1 - Dietrich, U. A1 - Fechtelkord, M. A1 - Müller, Ralf A1 - Deubener, J. T1 - Water in oxide glasses: from borosilicates to silicoborates N2 - In this poster, results are presented on the influence of water incorporation on the structure of B2O3 and SiO2 containing oxide glasses, which were found during the joint project at the locations Hanover, Clausthal and Berlin within the priority program SPP1594. T2 - 9th Otto Schott Colloquium CY - Jena, Germany DA - 09.09.2019 KW - IR KW - Glass KW - Water content KW - NMR PY - 2019 AN - OPUS4-50465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan T1 - Glass N2 - Überblick über die Arbeitsschwerpunkte des Fachbereichs 5.6 Glas und die Vielfalt des Werkstoffs Glas. An Hand der Vakuumheißgasextraktion (VHE) werden einige Beispiele u.a. zur Bestimmung des Wassergehalts oder des Diffusionskoeffizienten von Wasserstoff in Gläsern gezeigt. Zum Schluss erfolgt ein Ausblick auf die im nächsten Jahr zur Verfügung stehende robotergestützte Glasscreening Anlage. N2 - Overview about the key activities of division 5.6 glass and the diversity of the material glass. For the vacuum hot extraction method (VHE-MS) some examples are presented e. g. for the measurement of water content or the determination of diffusion coefficient of hydrogen in glasses. Finally, an outlook is shown on the robot controlled glass screening device which will be available next year. T2 - BAM - IFW Workshop CY - Berlin, Germany DA - 25.11.2019 KW - Glass KW - Glass screening device KW - Vacuum hot extraction PY - 2019 AN - OPUS4-50452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheffler, F. A1 - Fleck, M. A1 - Santiago, C. F. A1 - Brauer, D. S. A1 - Müller, Ralf T1 - Morphologies of Fresnoite surface crystals of BT0.75S glass under different atmospheric conditions N2 - Fresnoite glass-ceramics are characterized by piezoelectric, pyroelectric and non-linear optical properties. These properties can be adjusted by orienting the fresnoite crystals during crystallization. Crystallization begins at the surface. The first surface crystals are not oriented perpendicular and, therfore, produce a surface layer that has not the intended properties. To overcome this issue, the formation of fresnoite surface crystals at different atmospheric conditions was studied. T2 - 9th Int. Otto Schott Colloquium CY - Jena, Germany DA - 09.09.2019 KW - Glass KW - Surface crystallization KW - Crystal orientation PY - 2019 AN - OPUS4-50460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Welter, T. A1 - Marzok, Ulrich A1 - Deubener, J. A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Hydrogen diffusivity in sodium aluminosilicate glasses N2 - Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartzalbite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized). Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4×10−12 to 3×10−14m2 s−1 (Qz-Np) and from 4×10−13 to 3×10−15m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of Magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend. KW - Aluminosilicate glasses KW - Hydrogen diffusivity KW - Ionic porosity PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119502 VL - 521 SP - 119502 PB - Elsevier B.V. AN - OPUS4-50392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Deubener, J. A1 - Müller, Ralf A1 - Behrens, H. T1 - Statistical analysis of propagation rates of indentation-induced radial cracks N2 - Due to the stochastic nature of crack nucleation by Vickers indentation, a statistical analysis of propagation rates of 185 radial cracks was performed. Crack growth was observed directly using a video camera with high Image acquisition rate. It is found that propagation rates are controlled by the environmental reactions at the crack-tip shortly after their initiation (< 1 s). Calibration of the stress intensity KI showed that the residual stress factor χ and the exponent n of the equation KI==χPc−n (with P==load and c==crack length) are broadly distributed among the 185 analyzed cracks, ranging from 10−16 to 104 and from 0.1 to 5, respectively. For the most frequent crack, the equation KI==0.052Pc−1.47 holds. The results show that correlations of indentation-induced crack length to stress intensity necessitate the use of statistical significant data that are calibrated by the environmental reactions at the crack-tip. KW - Stress intensity factor KW - Vickers indentation KW - Subcritical crack growth KW - Soda-lime-silica glass PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119739 VL - 527 SP - 119739 PB - Elsevier B.V. AN - OPUS4-50393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Glass Sintering with Concurrent Crystallization and Foaming N2 - Glass powders are promising candidates for manufacturing a broad diversity of sintered materials like sintered ¬glass-ceramics, glass matrix composites or glass bonded ceramics with tailored mechanical, thermal, electrical and optical properties and complex shape. Its wide and precise adjustability makes this class of materials a key component for advanced technologies. Processing of glass or composite powders often allow even more flexibility in materials design. At the same time, however, processing can have substantial effects on the glass powder surface and sinterability. Thus, mechanical damage and surface contamination can strongly enhance surface crystallization, which may retard or even fully prevent densification. Whereas sintering and concurrent crystallization have been widely studied, partially as cooperative effort of the TC7 of the ICG, and although glass powder sintering is predominantly applied for glasses of low crystallization tendency, sintering is also limited by gas bubble formation or foaming. The latter phenomenon is much less understood and can occur even for slow crystallizing glass powders. The lecture illustrates possible consequences of glass powder processing on glass sintering, crystallization and foaming. T2 - 93rd Annual Meeting German Soc Glass Technol in conjunction with annual meeting French Union for Sci and Glass technol CY - Nuremberg, Germany DA - 13.05.2019 KW - Blähen KW - Glass KW - Kristallisation KW - Sintern PY - 2019 AN - OPUS4-50433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Vacuum hot extraction: Detection of volatiles N2 - Der Vortrag gibt einen Überblick über die Möglichkete und Grenzen der Methode der Vakuum-Heiß-Extraktion an der BAM T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - Berlin, Germany DA - 25.01.2019 KW - Heißgasextraktion KW - Glas PY - 2019 AN - OPUS4-50434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Reinsch, Stefan T1 - Dynamic Mechanical Analysis (DMA): Viscoelasticity N2 - Der Vortrag gibt einen Überblick über die am FB 56 der BAM betriebene Dynamisch-Mechanische Analyse mit dem Schwerpunkt auf Anwendungen für Glas N2 - The talk presents an overview over the method of Dynamic Mechanical Analysis used at the BAM division 5.6 Glass mainly focussed on glasses. T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - Berlin, Germany DA - 25.01.2019 KW - Dynamisch Mechanische Analyse KW - Dynamic mechanical analysis KW - Glas PY - 2019 AN - OPUS4-50436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deubener, J. A1 - Müller, Ralf A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Behrens, H. A1 - Balzer, R. A1 - Bauer, U. A1 - Kiefer, P. T1 - Micromechanical properties of hydrous oxide glasses N2 - Presentation of the results on structure and mechanical properties of water-bearing oxide glasses, which were found during the project at the locations Clausthal, Hanover and Berlin within the priority program SPP1594. T2 - 9th Otto Schott Colloquium CY - Jena, Germany DA - 09.09.2019 KW - Crack growth KW - Glass KW - Water content KW - Mechanical properties KW - IR PY - 2019 AN - OPUS4-50444 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 - 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 - CONF A1 - Grun, Benthe Birger A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen ED - Christ, Hans-Jürgen T1 - Charakterisierung von Hochtemperaturwerkstoffen durch Zug- und Ermüdungsversuche an Kleinproben T1 - Characterization of high-temperature materials by tensile and fatigue tests on small specimens N2 - Die Verwendung von miniaturisierten Probengeometrien in der mechanischen Prüfung ermöglicht die Entnahme des Probenmaterials direkt aus kritischen Bereichen wie Fügeverbindungen und ermöglicht die Prüfung von kleinen Bauteilen wie additiv gefertigten Strukturen. In der vorliegenden Arbeit werden exemplarisch die Ergebnisse von vergleichenden Zug- und niederzyklischen Schwing-versuchen (LCF) an dem austenitischen Stahl AISI 316L und der Nickelbasislegierung IN718 vorgestellt. Die Prüfergebnisse der Kleinproben aus AISI 316L weisen die charakteristischen Eigenschaften des Werkstoffs auf, und die Analyse der Zug- und Ermüdungsdaten führt zu Werten, die den Literaturdaten weitgehend entsprechen. Der direkte Vergleich mit Standardprobendaten zeigt jedoch systematische Abweichungen bei Zugfestigkeit, Dehngrenze und Gleichmaßdehnung, die in diesem Beitrag diskutiert werden. N2 - The use of miniaturized specimen geometries in mechanical testing allows to extract speci-men material directly from critical areas such as weldments and to test small structures such as additively manufactured components. In the present paper, example results of comparative tensile and low-cyclic fatigue tests (LCF) on the austenitic steel AISI 316L and the nickel-based alloy IN718 are presented. The test results of the small specimens on AISI 316L show the characteristic properties of the material, and the analysis of the tensile and fatigue tests leads to values which largely correspond to literature data. However, the direct comparison with standard sample data shows systematic deviations in tensile strength, yield strength and uniform elongation, which are discussed in this paper. T2 - Werkstoffprüfung 2019 CY - Neu-Ulm, Germany DA - 03.12.2019 KW - Kleinprobenprüfung KW - Probengrößeneffekt KW - Low Cycle Fatigue KW - Zugversuch KW - AISI 316L KW - IN 718 PY - 2019 SP - 329 EP - 334 AN - OPUS4-50220 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grun, Benthe Birger A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit A1 - Avila, Luis A1 - Charmi, Amir T1 - Charakterisierung von Hochtemperaturwerkstoffen durch Zug- und Ermüdungsversuche an Kleinproben N2 - Die Verwendung von miniaturisierten Probengeometrien in der mechanischen Prüfung ermöglicht die Entnahme des Probenmaterials direkt aus kritischen Bereichen wie Fügeverbindungen und ermöglicht die Prüfung von kleinen Bauteilen wie additiv gefertigten Strukturen. In der vorliegenden Arbeit werden exemplarisch die Ergebnisse von vergleichenden Zug- und niederzyklischen Schwingversuchen (LCF) an dem austenitischen Stahl AISI 316L und der Nickelbasislegierung IN718 vorgestellt. Die Prüfergebnisse der Kleinproben aus AISI 316L weisen die charakteristischen Eigenschaften des Werkstoffs auf, und die Analyse der Zug- und Ermüdungsdaten führt zu Werten, die den Literaturdaten weitgehend entsprechen. Der direkte Vergleich mit Standardprobendaten zeigt jedoch systematische Abweichungen bei Zugfestigkeit, Dehngrenze und Gleichmaßdehnung, die in diesem Beitrag diskutiert werden. T2 - Werkstoffprüfung 2019 CY - Neu-Ulm, Germany DA - 03.12.2019 KW - Kleinprobenprüfung KW - Probengrößeneffekt KW - Low Cycle Fatigue KW - Zugversuch KW - AISI 316L KW - IN 718 PY - 2019 AN - OPUS4-50221 LA - deu 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 - CHAP A1 - Skrotzki, Birgit A1 - Czichos, Horst ED - Hennecke, Manfred ED - Skrotzki, Birgit T1 - Materialprüfung N2 - Die Materialprüfung dient der Analyse der Eigenschaften, der Qualität und der Sicherheit vonMaterialien undWerkstoffen. Die häufigsten Verfahren umfassen die Analyse der chemischen Zusammensetzung und der Mikrostruktur sowie die Ermittlung von Werkstoffkennwerten. Dazu zählt auch die Bestimmung des Materialverhaltens unter verschiedenen Beanspruchungen bis hin zu komplexen Beanspruchungen. Die Verwendung von Referenzmaterialien, Referenzorganismen und Referenzverfahren dient der Zuverlässigkeit und Richtigkeit von Messungen, Prüfungen und Analysen. KW - Materialprüfung KW - Werkstoffprüfung KW - Chemische Analyse KW - Mikrostrukturuntersuchung KW - Gefügeuntersuchung KW - Werkstoffmechanische Prüfung KW - Zerstörungsfreie Prüfung KW - Referenzmaterial KW - Referenzorganismus KW - Referenzverfahren PY - 2019 SN - 978-3-662-57492-8 DO - https://doi.org/10.1007/978-3-662-57492-8_30-1 SP - 1 EP - 27 PB - Springer-Verlag GmbH CY - Berlin, Heidelberg ET - 35 AN - OPUS4-50516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klingelhöffer, Hellmuth T1 - Temperaturschwankungen an Extensometern - ein vielfach vernachlässigtes Thema N2 - Extensometer sind seit Jahrzehnten im Einsatz und bilden die Basis für eine präzise Dehnungsmessung in werkstoffmechanischen Versuchen. Jedoch ist die Temperaturstabilität von Extensometern häufig noch nicht ausreichend beachtet worden, um Fehler verursacht durch Temperaturschwankungen zu minimieren. Dieses wird derzeit nicht nur in Deutschland, sondern auch international zunehmend diskutiert. Datenblätter von Extensometern sind teils unvollständig besonders hinsichtlich von Temperatureinflüssen. Extensometer für den Einsatz bei höheren Temperaturen sollen z.B. laut Normen für dehnungsgeregelte Ermüdungsversuche mit Luft oder Wasser aktiv gekühlt werden. Jedoch schreiben die Normen keine Temperatur-Toleranzen für Extensometer vor. Dehnungsfehler verursacht durch Temperaturschwankungen am Extensometer bleiben meist verborgen, da die Temperatur des Extensometers standardmäßig gar nicht gemessen wird. Die Ursache von Einflüssen zur Temperaturstabilität von Extensometern wird erläutert. Ein einfaches Rechenbeispiel zeigt die Empfindlichkeit von Extensometern gegenüber Temperaturschwankungen und die Auswirkungen auf den Dehnungsfehler. Lösungsmöglichkeiten zur Optimierung werden aufgezeigt. Der Anwender von Extensometern soll sensibilisiert werden, um der Temperaturstabilität von Extensometern sowohl hinsichtlich Herstellerspezifikationen als auch bei der Anwendung von Extensometern im Prüflabor mehr Aufmerksamkeit zu schenken, um letztlich die Qualität von Versuchsergebnissen zu verbessern. Empfehlungen an Extensometerhersteller werden formuliert. Dieses Thema wird zukünftig auch in Prüfnormen mehr Aufmerksamkeit geschenkt werden. Es werden Maßnahmen zur Verbesserung der Temperaturstabilität von Extensometern Einzug in Prüfnomen finden, um letztlich verlässlichere Versuchsergebnisse zu erhalten. Es ist beabsichtigt, eine Verbesserung der Temperaturstabilität von Extensometern z.B. bei der nächsten Revision der Prüfnormen ISO 12106 und ISO 12111 für dehnungsgeregelte LCF- und TMF-Versuche zu berücksichtigen. T2 - Werkstoffprüfung 2019 CY - Neu-Ulm, Germany DA - 03.12.2019 KW - Extensometer KW - Temperaturschwankungen KW - Dehnungsfehler PY - 2019 AN - OPUS4-49961 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klingelhöffer, Hellmuth T1 - Temperaturschwankungen an Extensometern - ein vielfach vernachlässigtes Thema N2 - Extensometer werden seit langer Zeit erfolgreich für die Ermittlung von werkstoffmecha-nischen Kennwerten eingesetzt. Allerdings wurden in den letzten Jahren immer wieder durch Temperaturschwankungen bedingte Drift an Extensometern festgestellt, die be-sonders in Langzeitversuchen zu Problemen führen können. Es wurden Ursachen für die thermische Drift von Extensometern aufgezeigt. Anhand von einem Beispiel wurde gezeigt, wie sich Temperaturschwankungen an einem Extensometer auf die Ergebnisse von werkstoffmechanischen Ermüdungsversuchen auswirken können. An einem weiteren Beispiel wurde beschrieben, dass der durch Temperaturschwankungen verursachte Dehnungsfehler eines Extensometers stark von der Höhe der Temperaturschwankung und von der Dehnungsschwingbreite abhängt und, je nach Anwendungsfall größer als 1% werden kann. Es wurde verdeutlicht, dass bisherige nach Norm vorgeschriebene Maß-nahmen oft nicht ausreichen, um Einflüsse von Temperaturschwankungen am Extenso-meter zuverlässig zu unterbinden. Vorschläge wurden aufgezeigt, um die Temperatursta-bilität von Extensometern zu verbessern. Das gesamte Temperaturmanagement von Raumtemperatur, Kühlwassertemperatur, Temperaturmessung am Extensometer etc. sollte von Grund auf neu betrachtet werden, um Verbesserungen bei der Temperatur-konstanz von Extensometern zu erlangen. Ferner wurde vorgeschlagen, Extensometer in temperaturkompensierter Ausführung zu entwickeln und zu verkaufen. Dieses sollte Ret-rofits für existierende Extensometer miteinschließen. Konkrete Maßnahmen zur Imple-mentierung in Materialprüfungsnormen müssen weiter diskutiert werden. T2 - Tagung Werkstoffprüfung 2019 CY - Neu-Ulm, Germany DA - 03.12.2019 KW - Extensometer KW - Temperaturschwankungen KW - Dehnungsfehler PY - 2019 SN - 978-3-88355-418-1 SP - 361 EP - 366 PB - Inventum GmbH CY - Sankt Augustin AN - OPUS4-49965 LA - deu 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 - 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 - 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 - JOUR A1 - Hmood, F. A1 - Schmidt, Franziska A1 - Görke, O. A1 - Günster, Jens T1 - Investigation of chemically modified ICIE16 bioactive glass, part II N2 - Chemically modified bioactive glasses based on ICIE16 were prepared with the melt-quenching method using water as a quenching medium. The sinterability of these bioactive glasses was investigated and is discussed in this article. The sintering experiments were conducted with different sintering temperatures, sintering times and heating rates. Those parameters are crucial for dense glass with an amorphous structure. The particle size (d50) of the starting glass powder was determined at 88 μm and kept constant. The pre-pressed glass pellets were cold-isostatically pressed at 300 MPa to a green density of around 63 %. Density development, phase identification, shrinkage behavior and the microstructure were investigated to determine the sinterability of the developed glasses. The glass powders were sintered at different temperatures inside the processing window while crystallization was monitored. The results have shown that the sinterability of the developed glasses strongly dependsonthe proposed chemical additions. The highest density reached was 96 %, which belongs to BP1 glass with sintering conditions of 20 K/min heating rate for 60 min at 750 °C. KW - Bioactive glass KW - Viscous sintering KW - Crystallization KW - Processing window KW - Grain boundary PY - 2019 DO - https://doi.org/10.4416/JCST2019-00031 VL - 11 IS - 1 SP - 1 EP - 9 PB - Göller Verlag AN - OPUS4-49913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Materialschädigung durch Hochtemperaturkorrosion von koventionellen und innovativen Legierungssystemen N2 - Konventionelle und innovative Hochtemperaturwerkstoffe sind im technischen Betrieb einer Vielzahl an Belastungen ausgesetzt. Neben mechanischen Beanspruchungen stellt die chemische Belastung durch das Vorhandensein von aggressiven und korrosiven Medien (SO2, CO2, O2, H2O…) bei hoher Temperatur einen Schlüsselfaktor dar, der die Langlebigkeit der Materialien im Einsatz beeinflusst. Neben konventionellen, mikroskopischen Analyseverfahren bieten röntgenbasierte Techniken Möglichkeiten, die Grenzflächenreaktionen zwischen dem Werkstoff und den Medien während der chemischen Belastung (in situ) zu untersuchen. Neuartige Einblicke in die zugrunde liegenden Prozesse der Schädigungsmechanismen werden anhand von klassischen ferritischen Legierungen beschrieben. Das Verständnis von Schlüsselfaktoren zur Induzierung eines Schutzmechanismus ist insbesondere für die Entwicklung von neuartigen Materialklassen wie Hochentropie- und chemisch komplexe Legierungen notwendig. Erste Einblicke in Schädigungsmechanismen durch Gaskorrosion dieser innovativen Materialsysteme werden vorgestellt. T2 - AWT-VDI Werkstofftechnik Arbeitskreis Bremen CY - Leibnitz Institut für Werkstofforientierte Technologien, Germany DA - 27.11.2019 KW - In situ KW - Heißgaskorrosion KW - Hochentropielegierungen KW - XRD PY - 2019 AN - OPUS4-49844 LA - deu 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 - 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 - 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 - von Hartrott, P. A1 - Rockenhäuser, Christian A1 - Metzger, M. A1 - Skrotzki, Birgit T1 - Assessment of EN AW-2618A for high temperature applications considering aging effects N2 - The alloy EN AW-2618A was assessed regarding its properties for high temperature applications considering aging effects. T2 - BAM TMF-Workshop 2019 CY - Berlin, Germany DA - 13.11.2019 KW - Alloy 2618A KW - Degradation KW - Coarsening KW - Transmission electron microscopy KW - Dark-field transmission electron microscopy (DFTEM) PY - 2019 AN - OPUS4-49808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hilgenberg, Kai A1 - Daum, Werner A1 - Maierhofer, Christiane A1 - Altenburg, Simon A1 - Bruno, Giovanni A1 - Heckel, Thomas A1 - Skrotzki, Birgit A1 - Zerbst, Uwe A1 - Kranzmann, Axel A1 - Bettge, Dirk A1 - Sommer, Konstantin A1 - Seeger, Stefan A1 - Nitsche, Michael A1 - Günster, Jens A1 - Evans, Alexander T1 - Additive manufacturing at the BAM: We focus on Safety N2 - In Germany, the Federal Institute for Materials Research and Testing (BAM) is addressing challenges in the implementation of additive manufacturing on the industrial landscape for safety-critical applications. KW - Process development KW - Additive Manufacturing KW - In-situ Process Monitoring KW - Non-destructive Materials KW - Characterisation KW - Safety KW - Fatigue KW - Environment KW - Standardisation PY - 2019 UR - https://static.asminternational.org/amp/201910/22/ SN - 0882-7958 VL - 177 IS - 7 SP - 22 EP - 26 PB - ASM International CY - Materials Park, OH, USA AN - OPUS4-49780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trappe, Volker T1 - Fatigue life evaluation of composite wing spar cap materials N2 - An effective method for evaluating the fatigue strength of thick unidirectional composite laminates of wing spar caps has been presented here. A typical width-tapered bending specimen has been developed for a four-point loading set up. Static and fatigue loading was performed at a load ratio R = -1. The complex stress state has been investigated numerically by finite element analysis. Finally, the concept is proven experimentally on specimens made of pultruded fibre rods. The fatigue behavior of the continuously tapered width by water Jet cutting has been compared to discrete tapering via rod-drop. The new method enables a screening of material fatigue behavior caused by normal and shear loading. KW - Fatigue Testing KW - Pultruded fiber rods KW - CFRP KW - Four-point bending test KW - Spar cap design PY - 2019 DO - https://doi.org/10.3139/120.111431 SN - 0025-5300 VL - 61 IS - 12 SP - 1135 EP - 1139 PB - Carl Hanser Verlag CY - München AN - OPUS4-50090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Trappe, Volker A1 - Spancken, D. A1 - Zeiser, A. A1 - Kose, K. A1 - DeMonte, M. T1 - Kurzfaserverstärkte Thermoplaste - Zug-Druck-Schubprüfung mit einem Rohrprobekörper unter schwingender Beanspruchung N2 - Diese DIN SPEC legt ein Verfahren für die Prüfung von unverstärkten und partikel- und kurzfaserverstärkten Kunststoffen mittels Zug-Druck-Schubprüfung fest. Dieses Verfahren findet Anwendung zur Bestimmung der Schwingfestigkeit im Bereich von 103 bis 107 Schwingspielen und der Nachgiebigkeiten unter statischer Belastung sowie der Zugfestigkeit. Alle Beanspruchungen und berechneten Größen sind nennspannungs-basiert. Grundsätzlich besteht bei Rohrprobekörpern auch die Möglichkeit eine Beanspruchung in Längs- und in Umfangsrichtung durch Innendruck zu erzeugen. Dies wird in dieser Spezifikation nicht berücksichtigt, um die Anwendung überschaubar zu halten. Bei Rohrproben mit ausgeprägter Querschnittsverkleinerung (z. B. der Prüfkörper Typ B), entsteht eine Umfangsspannung auch aufgrund einer Zugkraft (siehe Anhang C). Die Umfangsspannung muss dann mittels FEA lokal berechnet werden. Das Verfahren gilt für rohrförmige Prüfkörper deren spezifische Form den Anforderungen der Werkstoff-prüfung und bei Kurzfaserverstärkung einer hohen Vorzugsausrichtung in Probenlängsrichtung genügen. Diese DIN SPEC gilt nicht für endlosfaserverstärkte Kunststoffe. Wegen der vollkommen unterschiedlichen Fertigungstechnologien und der zu erwartenden hohen Prüflasten, sind hier die Anforderungen an die Prüfkörpergeometrie gesondert zu betrachten. Es wird nicht zielführend sein, beide Werkstoffklassen in einer Norm zu behandeln. KW - Kurzfaser-verstärkte Thermoplaste KW - Zug-Druck-Schubprüfung KW - Betriebsfestigkeit KW - Rohrprobekörper PY - 2019 DO - https://doi.org/10.31030/3085076 IS - DIN SPEC 16457:2019-12 SP - 1 EP - 58 PB - Beuth CY - Berlin AN - OPUS4-50092 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Fatigue life evaluation and certification according to CS22 N2 - The common fatigue life certification of aircrafts according to the certification Standards 23 and 25 follows a building block approach. Static tests at room temperature as well in humid and high temperature conditions are done on the coupon level. Additionally, a full-scale static and fatigue test must be performed on the complete airframe (minimum on the fuselage together with the wing). For each type-certificate the complete building block approach test program must be performed. Traditionally in Germany, the certification of sailplanes (Certification Standard 22) follows rather a family concept. A shared data base was created over the last 50 years based upon a large number of material testing. In addition to static tests at room temperature and hot-humid conditions, fatigue tests are also done on the coupon level. Additional static and fatigue tests were done on complex structures such as spar-beams, fuselages and full-scale wing structures. However, for each type-certificate, only static tests should be performed in full-scale. This concept is determined by the certification memorandum CM-S-006 “Composite Lightweight Aircraft” 2017. The presentation was given as an introduction to the discussion about the future expectations and developments of the EASA concerning the type-certification of lightweight aircrafts according to CS22 at the OSTIVE Sailplane Development Panel Meeting at the EASA in Cologne on the 11th of October 2019. T2 - OSTIV Sailplane Development Panel Meeting 2019, Europäische Agentur für Flugsicherheit (EASA) CY - Cologne, Germany DA - 11.10.2019 KW - Certification Standard 22 KW - EASA KW - Sailplane Development Panel KW - Fatigue Life Evaluation PY - 2019 AN - OPUS4-50147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zemke, F. A1 - Schölch, V. A1 - Bekheet, M.F. A1 - Schmidt, Franziska T1 - Surfactant-assisted sol–gel synthesis of mesoporous bioactive glass microspheres N2 - Spherical mesoporous bioactive glasses in the silicon dioxide (SiO2)-phosphorus pentoxide (P2O5)–calcium oxide (CaO) system with a high specific surface area of up to 300m2/g and a medium pore radius of 4 nm were synthesized by using a simple one-pot surfactant-assisted sol–gel synthesis method followed by calcination at 500–700°C. The authors were able to control the particle properties by varying synthesis parameters to achieve microscale powders with spherical morphology and a particle size of around 5–10 mm by employing one structure-directing agent. Due to a high Calcium oxide content of 33·6mol% and a phosphorus pentoxide content of 4·0mol%, the powder showed very good bioactivity up to 7 d of immersion in simulated Body fluid. The resulting microspheres are promising materials for a variety of life science applications, as further processing – for example, granulation – is unnecessary. Microspheres can be applied as materials for powder-based additive manufacturing or in stable suspensions for drug release, in bone cements or fillers. KW - bioactive KW - biomaterials KW - bone PY - 2019 DO - https://doi.org/10.1680/jnaen.18.00020 SN - 2045-9831 SN - 2045-984X VL - 8 IS - 2 SP - 126 EP - 134 PB - ICE Publishing CY - London AN - OPUS4-50148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Faserkunststoffverbunde (FKV) in Forschung und Anwendung N2 - Der Fachbereich Mechanik der Polymerwerkstoffe befasst sich mit der Charakterisierung der mechanischen Eigenschaften und der Degradation von Polymeren und Faserverbundwerkstoffen, die in hochbeanspruchten, sicherheitsrelevanten Konstruktionen wie jenen des Flugzeugbaus, des Automobilbaus und der Windenergie-Industrie eingesetzt werden. Auch die Analyse der chemischen und physikalischen Eigenschaften von Polymeren zählt zu unserem Aufgabenbereich. Das Spektrum reicht von der statischen Festigkeit über die Betriebsfestigkeit, die Messung bruchmechanischer und viskoelastischer Parameter bis hin zur Formulierung molekularer Schädigungsmechanismen. T2 - VDI Arbeitskreis Kunststofftechnik, BAM, Unter den Eichen 87 CY - Berlin, Germany DA - 14.08.2019 KW - Faserkunststoffverbunde KW - Werkstoffprüfung KW - Normung PY - 2019 AN - OPUS4-50128 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Effective composite testing – from specimen size to component scale N2 - Even for the basic measurements of material data for design and engineering of composite structures there is a need to upgrade standards. With a new shear frame test rig more precise values can be obtained. With advanced methods in the research on the fatigue behaviour of FRP it was found a load level of infinite life for GFRP and CFRP. This is in the range of typical strain values of airliners and rotor blades in normal operation. Statistically the mean time between damage events on rotor blades is 6 years (Deutscher Windenergie Report 2006). Due to imperfection in the production the shell structures get cracks after a few years fare before the designed life time. A shell test rig was built at BAM for efficient research on the effects of defects in production. Test blades of ~10m are an efficient way for SHM research and evaluation of NDT-methods and blade geometry. T2 - colloquium genesis-puc CY - Rio de Janeiro, Brazil DA - 01.11.2019 KW - Polymer matrix composites KW - Nondestructive testing KW - New standards PY - 2019 AN - OPUS4-50129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Polymer matrix composites investigated with NDT at BAM N2 - Statistically the mean time between damage events on rotor blades is 6 years (Deutscher Windenergie Report 2006). Due to imperfection in the production the shell structures get cracks after a few years fare before the designed life time. A shell test rig was built at BAM for efficient research on the effects of defects in production. In-situ and ex-situ NDT give a better understanding from degradation processes in composite materials. With advanced methods in the research on the fatigue behaviour of FRP it was found a load level of infinite life for GFRP and CFRP. This is in the range of typical strain values of airliners and rotor blades in normal operation. Due to the fibre-composite nature NDT techniques have to be suitable to a wide length scale to image micro cracking as well as bigger defects. Therefore different techniques have to be applied and developed. T2 - Colloquium Abendi CY - São Paulo, Brazil DA - 05.11.2019 KW - Polymer matrix composites KW - Non-destructive testing PY - 2019 AN - OPUS4-50130 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 - 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 - 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 - CONF A1 - Olbricht, Jürgen A1 - Sonntag, Nadja A1 - Nolze, Gert A1 - Agudo Jácome, Leonardo A1 - Roohbakhshan, Farshad A1 - Fedelich, Bernard A1 - Skrotzki, Birgit A1 - Jürgens, Maria T1 - Cyclic mechanical performance and microstructure evolution of P92 under LCF and TMF conditions 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 contribution 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 this 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 fatigue and creep/relaxation 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). Temperature intervals of TMF tests were chosen as either 300-620°C or 500-620°C, resembling so-called warm or hot start conditions of a power plant. The test results will be presented and discussed with a focus on the impact of hold periods during testing (combined creep/relaxation-fatigue conditions) on mechanical softening, lifetime and formation of cracks. The findings will be complemented by results on the modification of the hierarchical ferritic-martensitic microstructure under different loading scenarios. T2 - 4th International Workshop on Thermo-Mechanical Fatigue 2019 CY - Berlin, Germany DA - 13.11.2019 KW - Power plant KW - Tempered martensite ferritic steels KW - Thermo-Mechanical Fatigue KW - Microstructure modification KW - EBSD PY - 2019 AN - OPUS4-50053 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 - 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 - Balzer, R. A1 - Behrens, H. A1 - Reinsch, Stefan A1 - Fechtelkord, M. T1 - Structural investigation of hydrous phosphate glasses N2 - Dissolved water has major impact on the physical and chemical properties of phosphate glasses. In the present study we have investigated the structural response to water incorporation for glasses in the system Li2O–MgO–Al2O3–P2O5. Glasses containing 0–8 wt% H2O were synthesised at 500 MPa confining pressure in internally heated gas pressure vessels at 1323 K (LMP, Al-poor glass) and 1423 K (LMAP, Al-enriched glass). Water contents of glasses were determined by pyrolysis and subsequent Karl-Fischer titration (KFT) and/or by infrared spectroscopy. Density varies nonlinearly with water content implying large structural changes when adding up to 2 wt% H2O to the dry glass. Glass Transition temperatures measured by differential thermal analysis (DTA) continuously decrease with water content. The trend can be explained by depolymerisation of the phosphate network. Near-infrared spectroscopy shows that even in Al poor glasses only a minority of dissolved water is present as H2O molecules, but the largest amount is present as OH Groups formed by hydrolysis of P–O–P bonds. The network is stabilised by aluminium which is predominantly six-coordinated in these glasses as shown by 27Al MAS NMR spectroscopy. With increase of Al in the glasses, breaking up of the Phosphate network through hydrolysis is depressed, i.e. much lower OH Contents are formed at same total water content. Network depolymerisation upon addition of H2O is evident also from 31P MAS NMR spectroscopy. While Phosphate tetraheda are crosslinked by two to three bridging oxygen in dry glasses, diphosphate Groups are dominant in glasses containing 8 wt% H2O. T2 - 2. INT. CONF. ON PHOSPHATE GLASSES CY - Oxford, UK DA - 26.07.2017 KW - water speciation KW - phosphate glasses KW - infrared spectroscopy KW - NMR spectroscopy KW - high pressure PY - 2019 DO - https://doi.org/10.13036/17533562.60.2.041 SN - 1753-3562 VL - 60 IS - 2 SP - 49 EP - 61 PB - Society of Glass Technology CY - Sheffield AN - OPUS4-48122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Charmi, Amir A1 - Falkenberg, Rainer A1 - Skrotzki, Birgit T1 - Virtual-lab-based determination of a macroscopic yield function for additively manufactured parts N2 - This work aims for a yield function description of additively manufactured parts of S316L steel at the continuum-mechanical macro-scale by means of so-called virtual experiments using a crystal plasticity (CP) model at meso-scale. Additively manufactured parts require the consideration of the specific process-related microstructure, which prevents this material to be macroscopically treated as isotropic, because of crystallographic as well as topological textures. From virtual experiments, yield loci under various loading conditions are simulated. The scale bridging from meso- to macro-scale is realised by the identification of the simulated yield loci as a modified anisotropic Barlat-type yield model representation. T2 - Workshop on Additive Manufacturing, BAM CY - Berlin, Germany DA - 13.05.2019 KW - Virtual experiments KW - Additive manufacturing KW - Anisotropy KW - Crystal plasticity KW - Scale-bridging PY - 2019 AN - OPUS4-48064 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altenburg, Simon A1 - Mohr, Gunther A1 - Baesso, Ilaria A1 - Straße, Anne A1 - Pittner, Andreas A1 - Pignatelli, Giuseppe A1 - Seeger, Stefan A1 - Nazarzadehmoafi, Maryam A1 - Ehlers, Henrik A1 - Gohlke, Dirk A1 - Homann, Tobias A1 - Scheuschner, Nils A1 - Ulbricht, Alexander A1 - Heinrich, P. A1 - Maierhofer, Christiane T1 - Process monitoring of additive manufacturing of metals - an overview of the project ProMoAM N2 - The project ProMoAM is presented. The goal of the project is to evaluate which NDT techniques or combination of techniques is suited for in-situ quality assurance in additive manufacturing of metals. To this end, also 3d-data fusion and visualization techniques are applied. Additional ex-situ NDT-techniques are used as references for defect detection and quantification. Feasability studies for NDT-techniques that are presently not applicable for in-situ use are performed as well. The presentation gives a brief overview of the whole project and the different involved NDT-techniques. T2 - Workshop od Additive Manufacturing: Process, materials, simulation & implants CY - Berlin, Germany DA - 13.05.2019 KW - Additive manufacturing KW - Process monitoring KW - NDT PY - 2019 AN - OPUS4-48087 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 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Kalinka, Gerhard T1 - Deformation behavior of alumina and zirconia springs at room temperature N2 - At high temperatures and in harsh environments ceramic springs are often superior to metallic springs and allow for innovative solutions. A recently proposed application involves ceramic springs with metallized surfaces as capacitive force sensor. A strictly linear stress-strain characteristic of the spring is a precondition for such a sensor. Helical ceramic springs with rectangular cross-section have been produced from sintered hollow cylinders. Alumina, ATZ, Y-TZP, and Ce-TZP springs with identical dimensions were characterized and compared regarding deformation behavior. Spring deformation was investigated under various load scenarios. Dynamic compression was performed with deformation speeds from 0.3 to 30 mm/min. Spring constants of alumina springs are strain rate independent. By contrast, Y-TZP spring constant increases by approximately 3 % within the experimental framework. A high-precision test facility was developed to characterize spring displacement in nm range under static tensile load over long periods of time. Spring elongation with asymptotic course was observed for zirconia containing materials at room temperature. This effect is particularly strong in the case of Y-TZP. Up to 0.3 % time-dependent elongation was measured after 24 h under constant load. Deformation is completely reversible after unloading. Alumina springs do not show any time-dependent deformation under identical test conditions. Contrary to alumina springs, a non-linear stress-strain behavior of TZP springs at room temperature was proved in both test series. It is supposed, that pseudo-elasticity caused by stress-induced phase transformation from tetragonal to monoclinic is responsible for this special behavior of TZP springs. T2 - D-A-CH Keramiktagung CY - Leoben, Austria DA - 06.05.2019 KW - Phase transformation KW - Ceramic spring KW - Force-distance diagram KW - Deformation behavior PY - 2019 AN - OPUS4-48026 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 - 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 - 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 - 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 - 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 - 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. 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 - THES A1 - Sonntag, Nadja T1 - Untersuchung magnetischer Streufelder in einem inhomogen verformten Baustahl mittels passiv-magnetischer Prüfverfahren N2 - Die Metal Magnetic Memory (MMM) Methode ist ein standardisiertes, zerstörungsfreies Prüfverfahren, das für die Detektion von lokal geschädigten Materialbereichen in ferromagnetischen Bauteilen oder Proben verwendet wird. Es basiert auf der Annahme lokaler magnetoelastischer Wechselwirkungen an Spannungskonzentrationsstellen, die schwache magnetische Streufelder an den geschädigten Prüfkörperoberflächen hervorrufen. Die MMM-Methode überträgt dabei die für einachsige und elastische Verformungen entwickelten magnetoelastischen Modellvorstellungen ohne weitere Anpassungen in den Schädigungskontext, der jedoch mehrachsige Beanspruchungen und elastisch-plastische Deformationsprozesse erwarten lässt. Das Ziel der Arbeit ist es daher, die gängigen MMM-Hypothesen zur Signalentstehung fach- und skalenübergreifend und unter stärkerer Berücksichtigung mechanischer und mikrostruktureller Aspekte zu überprüfen. Zu diesem Zweck wurden zum einen gekerbte Flachzugproben aus einem unlegierten Baustahl inhomogen elastisch-plastisch verformt und die entstehenden magnetischen Streufelder an deren Oberflächen mit einem Drei-Achsen-GMR-Magnetometer detektiert. Die so ermittelten Magnetfeld-verteilungen wurden für unterschiedliche Verformungszustände ortsaufgelöst und richtungsabhängig mit gemessenen Dehnungsverteilungen (digitale Bildkorrelation) und mit simulierten Lastspannungs-verteilungen korreliert. Die eingeschnürten Probenbereiche wurden zusätzlich topographisch mittels Streifenlichtprojektion und Weißlichtinterferenzmikroskopie vermessen, um den Magnetisierungs-prozess ebenfalls vor dem Hintergrund geometrischer Effekte diskutieren zu können. Um systematische, verformungsinduzierte Veränderungen der magnetischen Mikrostruktur (magnetischer Domänen) im polykristallinen, quasi-isotropen Material nachzuweisen, wurde zum anderen ein in dieser Arbeit entwickelter statistischer Ansatz der Domänenanalyse angewandt. Hierfür wurde das Material zunächst durch Härteeindrücke mehrachsig elastisch-plastisch verformt, und die verformten Probenbereiche wurden anschließend mit Hilfe der Bitterstreifentechnik hauptsächlich bei niedriger Vergrößerung lichtmikroskopisch untersucht. Die beobachteten makroskopischen Domänen-kontraste wurden über ein analytisches, kontaktmechanisches (ECM-) Modell und über Makro-Eigen-spannungsmessungen (energiedispersive Synchrotron-Beugungsuntersuchungen) charakteristischen Verformungszonen unter den Härteeindrücken zugeordnet. Die Ergebnisse dieser Untersuchungen belegen, dass die Entstehung der Streufelder – entgegen bisheriger Annahmen – nicht allein auf mechanische Spannungs- und Verformungsgradienten im Material zurückzuführen, sondern auch topographisch bedingt ist. Die Vernachlässigung überlagerter geometrischer Effekte kann zu sicherheitsrelevanten Fehlinterpretationen der magnetischen Signale führen. Einachsige magnetoelastische Modellvorstellungen sollten zudem nicht ohne Anpassungen auf komplexe Beanspruchungen übertragen werden, da u. a. sowohl mechanische Größen (wie Spannungen oder Dehnungen) als auch mikrostrukturelle Parameter (wie z. B. Versetzungsdichten) bei komplexen Belastungen als ortsabhängige Variablen behandelt werden müssen. Die in dieser Arbeit beobachteten Domänenkontraste lassen sich zweifelsfrei charakteristischen Verformungszonen zuordnen, mikro-strukturell jedoch nicht allein mit anzunehmenden Gradienten der Versetzungsdichte erklären. Statt-dessen entstehen beispielsweise lokale Verformungstexturen, die zusätzliche magnetische Anisotropien bewirken könnten. Da bisher weder die makroskopischen noch die mikrostrukturellen Ursachen der Streufeldentstehung hinreichend verstanden sind, scheint die MMM-Methode für die quantitative Bewertung des Schädigungszustands derzeit ungeeignet. N2 - The Metal Magnetic Memory (MMM) method is a standardized, nondestructive testing method used for the detection of locally damaged material areas in ferromagnetic components or samples. It assumes local magnetoelastic interactions in stress concentration zones, causing weak magnetic stray fields on the damaged specimen surfaces. The MMM method transfers magnetoelastic model conceptions developed for uniaxial and elastic deformations without further adjustments into the damage context, which is, however, associated with multiaxial stresses and elastic-plastic deformations. The objective of this thesis is therefore to verify prevalent MMM hypotheses concerning the signal generation, putting emphasis on complex mechanical and microstructural aspects of damage while using interdisciplinary and multi-scale approaches. To this end, on the one hand, notched tensile specimens made of an unalloyed structural steel were inhomogeneously (elastically and plastically) deformed and deformation-induced magnetic stray fields were then detected by a three-axis GMR magnetometer. The obtained surface magnetic field distributions were correlated with measured strain distributions (digital image correlation) and with numerically simulated mechanical stress distributions (finite element analysis). To enable discussions on the magnetization process against the background of geometrical effects, the necked specimen regions were additionally investigated using optical profilometry methods (fringe projection and white light interference microscopy). On the other hand, a newly developed meso-scale approach to magnetic domain analysis was applied to prove systematic, deformation-induced changes of the magnetic microstructure within the polycrystalline, quasi-isotropic material: After multiaxial elastic-plastic deformation of coupon specimens by hardness indentation, the deformed sample regions were studied by Bitter technique in optical microscopy, preferably at low magnification. The observed macroscopic domain contrasts were related to characteristic deformation zones below the indents by using an analytical model from the field of contact mechanics (ECM) and macro-residual stress measurements (obtained from energy-dispersive synchrotron diffraction experiments). It is demonstrated that the formation of magnetic stray fields, quite contrary to previous assumptions, results not only from mechanical (e.g. stress) gradients within the material, but is also topographically induced. The neglect of such superimposed geometric effects may also lead to safety-relevant misinterpretations of the magnetic signals. Furthermore, uniaxial magnetoelastic model concepts should not be applied to complex stress/strain conditions without adaptation since both mechanical quantities (such as stresses or strains) and microstructural parameters (such as dislocation densities) must be treated as location-dependent variables. The observed magnetic domain contrasts could clearly be assigned to characteristic deformation zones but cannot be explained solely by hypothesized gradients of the dislocation density. Instead, for example, local deformation textures emerge, which may cause additional magnetic anisotropies. The MMM method currently seems unsuitable for quantitative damage assessments of components or specimens since neither the macroscopic nor the microstructural origins of the stray field formation have yet been sufficiently understood. KW - Magnetoelastischer Effekt KW - Magnetische Domänen KW - Mehrachsige Verformung KW - Schädigung KW - Unlegierter Baustahl KW - Magnetoelastic effect KW - Magnetic domains KW - Multiaxial deformation KW - Damage KW - Structural steel PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484302 DO - https://doi.org/10.14279/depositonce-8524 SP - 1 EP - 117 CY - Berlin AN - OPUS4-48430 LA - deu 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 - Fedelich, Bernard A1 - Feldmann, Titus A1 - Charmi, Amir A1 - Epishin, A. T1 - Simulation of pore shrinkage with crystal plasticity and dislocation transport N2 - Single crystal superalloys usually contain pores of sizes 5-10 micro-m after casting and heat treatment. These pores can be reduced under compression by combined creep and diffusion in a subsequent treatment called Hot Isostatic Pressing (HIP). The paper presents a methodology to simulate pore shrinkage under HIP conditions in two dimensions (2D). At the scale of the pores, which is also the scale of the sub-grains (<50 micro-m) the dislocation sources cannot be assumed to be homogeneously distributed. Thus, the applicability of classical crystal plasticity is questionable. In this case, the transport of dislocations under an applied stress from the location where they are nucleated must be explicitly modelled. This is done by solving the transport equations for the dislocation densities and the elasticity equations in 2D. The dislocations are assumed to be nucleated at Low Angle Boundaries. They glide or climb through the sub-grains with a stress dependent velocity. The transport equations are solved by the Flux-Corrected Transport method, which belongs to the predictor-corrector class of algorithms. In the first step, an artificial diffusion is introduced, which suppresses spurious oscillations of the solution. In a second step, the solution is corrected in such a way that no additional extremes appear and that the extremes do not grow. The algorithm is validated by simulating the transport of simple distributions with a constant velocity field. With the dislocation velocities and the computed dislocation densities, the inelastic shear rate at the slip system level is computed by integrating the Orowan equation. In the 2D-setting, three slip systems are considered. The contributions of these slip systems are summed up to obtain the total inelastic strain rate. Dislocation glide and climb and the coupling of climb with vacancies diffusion are considered. The resolution of the equilibrium equations from the inelastic strains turned out to be prone to numerical instabilities. As an alternative, the stresses are directly computed from the distribution of geometrically necessary dislocations following the method presented in. The resulting boundary value problem is solved by the Least-Square Finite Element method. Examples of simulations are presented for a representative region under creep tension and for a pore shrinking under external pressure. T2 - International Conference on Material Modelling, ICMM 6 CY - Lund, Sweden DA - 26.06.2019 KW - Superalloy KW - Pores KW - Creep KW - Dislocations PY - 2019 AN - OPUS4-48488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiefer, P. A1 - Balzer, R. A1 - Deubener, J. A1 - Behrens, H. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Density, elastic constants and indentation hardness of hydrous soda-lime silica glasses N2 - The effect of structural water on density, elastic constants and microhardness of water-bearing soda-lime-silica glasses of up to 21.5 mol% total water is studied. It is found that the Poisson ratio and the water content are positively correlated, while density and the elastic moduli decrease with increasing water content. Vickers hardness decreases by approximately 27% from the dry to the most hydrous glass. For water fractions <3 mol%, the dependencies are non-linear reflecting the non-linear change in the concentrations of OH and H2O molecules dissolved, whereas for water fractions >3 mol% linear dependencies are found. To distinguish the effect of structural water and environmental water, indentations were performed in toluene, nitrogen gas and air. Timedependent softening was evident for testing dry glasses in humid atmospheres as well as for tests of hydrous glasses in dry atmospheres. This indicates that the response times of dissolved water species are effectively equal in both scenarios. KW - Elastic constants KW - Soda-lime-silica KW - Glass KW - Water content KW - Microhardness PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.119480 SN - 0022-3093 SN - 1873-4812 VL - 521 SP - 119480 PB - Elsevier B.V. AN - OPUS4-48758 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -