TY - CONF A1 - Olbricht, Jürgen T1 - Combined corrosion-mechanical testing of boiler steels under oxyfuel atmospheres T2 - 3rd Osyfuel Young Researchers Forum, IFK Universität Stuttgart CY - Stuttgart, Germany DA - 2010-10-04 PY - 2010 AN - OPUS4-22446 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Olbricht, Jürgen A1 - Neddemeyer, Torsten A1 - Hünert, Daniela A1 - Klingelhöffer, Hellmuth A1 - Kranzmann, Axel A1 - Skrotzki, Birgit T1 - Mechanical properties of superheater materials after ageing and corrosion in CO2 rich flue gases T2 - First international conference on materials for energy CY - Karlsruhe, Germany DA - 2010-07-04 KW - Power generation KW - Superheater materials KW - Hot corrosion KW - Carburisation PY - 2010 SN - 978-3-89746-117-8 IS - Extended abstracts - Book A SP - 251 EP - 253 AN - OPUS4-21727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Mechanical Properties of Superheater Materials after Ageing and Corrosion in CO2 rich Flue Gases T2 - 1st Int. Conference on Materials for Energy CY - Karlsruhe, Germany DA - 2010-07-04 PY - 2010 AN - OPUS4-21709 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - The effect of high temperature corrosion in CO2 rich gases on the mechanical properties of super heater materials T2 - Materials Science and Engineering CY - Darmstadt, Germany DA - 2010-08-24 PY - 2010 AN - OPUS4-22312 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Size effects in miniature specimen creep testing of heat resistant ferritic-martensitic steels N2 - The use of miniaturized specimen geometries in mechanical testing allows extracting the sample material directly from the sidewall of critical components of power plants, like e.g. headers and steam pipes. In this way, both the impacts of the processing of the component (including all shaping and tempering influences) and of the exposure to the complex aging/loading/oxidation conditions in the plant (in case of post-Service tests) can be analyzed and representative mechanical properties are obtained. T2 - CREEP 2015 - 13th International conference on creep and fracture of engineering materials and structures CY - Toulouse, France DA - 31.05.2015 PY - 2015 SP - 163 EP - 164 AN - OPUS4-33528 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Size Effects in Miniature Specimen Creep Testing of Heat Resistant Ferritic-Martensitic Steels T2 - 13th International Conference on Creep and Fracture of Engineering Materials and Structures CY - Toulouse, France DA - 2015-05-31 PY - 2015 AN - OPUS4-33466 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Metallic high temperature materials for energy applications - current research activities at BAM T2 - 2nd European Steel Technology and Application Days (ESTAD) 2015 CY - Düsseldorf, Deutschland DA - 2015-06-15 PY - 2015 AN - OPUS4-33467 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pelegrina, J.L. A1 - Yawny, A. A1 - Olbricht, Jürgen T1 - Comment on: "Isothermal nature of the B2-B19' martensitic transformation in a Ti-51.2 Ni (at.%) alloy" N2 - Fukuda et al. published a paper (Scripta Mater. 68 (2013) 984–987) in which they claimed to be able to determine the isothermal nature of the martensitic transformation in a Ti–Ni alloy. They analyzed the evolution of electrical resistance during isothermal holding stages and concluded that the variations were a consequence of the isothermal transition between austenite and martensite. In the following we will demonstrate that the discussed data do not allow the interpretation presented and that the isothermal nature is not proved. KW - Thermal activation KW - Titanium–nickel alloy KW - Shape memory alloy KW - Nucleation PY - 2015 DO - https://doi.org/10.1016/j.scriptamat.2014.10.009 SN - 1359-6462 SN - 1872-8456 VL - 98 SP - 68 EP - 70 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Charakterisierung des Kriechverhaltens hochwarmfester Stähle durch Versuche an Miniaturproben N2 - Die Einsatzbedingungen der Bauteile von fossil befeuerten Kraftwerken unterliegen derzeit durch aktuelle Entwicklungen des Energiesektors (Stichwort „Energiewende“) erheblichen Veränderungen. Während das Interesse an einer weiteren Steigerung der Wirkungsgrade und den damit verbundenen Erhöhung der Prozessdrücke und -temperaturen prinzipiell anhält, werden parallel neue Verbrennungsprozesse wie z. B. die Oxyfuelverbrennung diskutiert und die Einsatzmöglichkeiten von Ersatzbrennstoffen wie Biomasse und hochkalorischen Müllfraktionen werden untersucht. Während diese Maßnahmen über veränderte Rauchgaszusammensetzungen ggf. zu einem generell verstärkten Hochtemperaturkorrosions-Angriff der Bauteile führen, zwingt der Ausbau der Stromerzeugung auf Basis von Wind- und Sonnenenergie die Anlagenbetreiber gleichzeitig zu einer lastflexiblen Anlagenfahrweise mit häufigen Warm- und Kaltstarts bei möglichst hohen Lastgradienten. Diese veränderten Betriebsbedingungen stellen eine Herausforderung für die Überwachung und Instandhaltung bestehender Kraftwerke sowie für die Konstruktion neuer Anlagen und Komponenten dar. N2 - Miniaturized specimen geometries in mechanicai testing allow extracting the sample material directly from critical components of power plants. In this way, both the Impacts of manufacturing and of the complex aging/loading/oxidation conditions during Service on life consumption are captured and representative mechanicai properties are obtained. In the present contribution, example results of a comparative creep/creep rupture study on P91 tempered martensite ferritic Steel, involving cylindrical Standard and miniature specimens (diameter 3 mm), are presented. The test results of miniature specimens exhibit all characteristic creep features of tempered martensite ferritic steels, and realistic stress and temperature dependences are obtained which correspond well to literature data. However, direct comparison with large scale specimen data reveals small but systematic variations in minimum creep rates, elongations at fracture and times to rupture. These differences are discussed in the light of literature findings on specimen size influences in other heat resistant alloys. Size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. T2 - Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe - Beiträge zur 37. Vortragsveranstaltung der Arbeitsgemeinschaft für warmfeste Stähle und Hochtemperaturwerkstoffe CY - Düsseldorf, Germany DA - 28.11.2014 PY - 2014 SP - 106 EP - 116 AN - OPUS4-32402 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pelegrina, J.L. A1 - Yawny, A. A1 - Olbricht, Jürgen A1 - Eggeler, G. T1 - Transformation activity in ultrafine grained pseudoelastic NiTi wires during small amplitude loading/unloading experiments N2 - Martensitic phase transformations were studied in ultrafine grained Ni-rich pseudoelastic NiTi wires during cyclic deformation under small imposed strain amplitudes. Small strain variation tests were complemented by a thermographic analysis of the emerging temperature distributions in the specimens. The characteristics of the observed thermal profiles result from the specific phase transitions which take place at different stress levels. Homogeneous temperature changes, corresponding to a non-localized transformation activity along the specimen length, were observed throughout the whole range of applied stresses, starting from values as low as 100 MPa. This behavior is in line with previous literature reports for the stress-induced transformation from B2 austenite to R-phase as long as the critical stress for B19' martensite formation is not reached. In the present study, similar type of transformation activity could also be demonstrated at higher strains/stresses, even after the stress induced transformation to B19' was apparently completed. These findings suggest that transformation activity involving the B2 phase is present throughout the whole pseudoelastic stress–strain cycle; i.e., it is not restricted to the initial loading portion. Finally, non-localized transformation to or from B19' was identified during small amplitude strain variations in the plateau-like coexistence ranges of the pseudoelastic cycle. KW - NiTi shape-memory alloys KW - Pseudoelasticity KW - Stress-induced phase transformations KW - R-phase KW - Thermal analysis PY - 2015 DO - https://doi.org/10.1016/j.jallcom.2015.08.159 SN - 0925-8388 SN - 1873-4669 VL - 651 SP - 655 EP - 665 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-34012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Untersuchungen zur Beständigkeit hochwarmfester 9-12% Cr-Stähle in zyklisch betriebenen Dampferzeugern lastflexibler Kraftwerke N2 - Konventionelle Kraftwerke sind durch die Energiewende erheblichen Anforderungen ausgesetzt. Mangels ausreichender Stromspeicherkapazitäten müssen sie zur Netzstabilisierung flexibel auf die wetter- und tageszeitbedingte Fluktuation der Wind- und Sonnenergie reagieren, was gegenüber dem Grundlastbetrieb eine hohe Anzahl von Lasteingriffen oder Anfahrvorgängen bedeutet. Schnelle Lastwechsel und Anfahrvorgänge führen jedoch zu einer erheblichen Beanspruchung aller Bauteile des Dampfkreislaufs, die zu einer beschleunigten Bauteilschädigung und bis hin zu Anlagenausfällen führen können. Vor diesem Hintergrund werden an der Bundesanstalt für Materialforschung und -prüfung (BAM) Untersuchungen zur Beständigkeit ferritisch-martensitischer Dampferzeuger-werkstoffe mit 9 12 Gew. % Cr (P91, P92, VM12 SHC) bei zyklischem Anlagenbetrieb durchgeführt. Ziel der Arbeiten ist, durch grundlegende Korrosions- und Mechanikversuche unter zyklischen Bedingungen und ergänzende Simulationen die Reaktion dieser Werkstoffgruppe auf lastflexible Betriebsprofile umfassend zu beschreiben. Aufbauend auf einer detaillierten Charakterisierung der auftretenden Schädigungsmechanismen werden in einem Folgeschritt Standardzyklen zur effizienten Prüfung einzelner Werkstoffe abgeleitet. Der Beitrag gibt einen kurzen Überblick über die Konzeption und stellt nachfolgend die aktuellen Projektergebnisse vor. Im Bereich der Oxidations-/Korrosionsuntersuchungen steht dabei zunächst die Integrität der schützenden Oxidschichten, vor allem auf der Dampfseite der Komponenten, im Vordergrund. Hierzu werden zyklische Oxidationstests an Standardproben und bauteilnahen Probengeometrien durchgeführt und die Oxidationskinetik sowie die Entwicklung der Haftfestigkeit untersucht. Die mechanischen Untersuchungen bauen auf den bekannten Kriech- und Ermüdungseigenschaften auf. Der Schwerpunkt liegt deshalb auf der Untersuchung von Schädigung und Lebensdauer bei Kombination von stationären Zuständen (mit überwiegender Kriechschädigung) und transienten Zuständen inklusive Temperaturwechseln, die Kriechermüdungs- bzw. thermo-mechanische Ermüdungsprozesse auslösen und so eine frühzeitige Rissbildung bewirken können. Im Hinblick auf die Flexibilisierung von Bestandsanlagen werden betriebsbeanspruchte Chargen in die Untersuchungen einbezogen, um eventuelle zusätzliche Effekte durch Werkstoffalterung zu berücksichtigen. T2 - 48. Kraftwerkstechnisches Kolloquium CY - Dresden, Germany DA - 18.10.2016 KW - Dampfkraftwerk KW - Lastflexibilität KW - Zyklische Dampfoxidation KW - Thermo-mechanische Ermüdung PY - 2016 AN - OPUS4-38353 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pelegrina, J. L. A1 - Olbricht, Jürgen A1 - Yawny, A. A1 - Eggeler, G. T1 - Temperature-induced transformations and martensitic reorientation processes in ultra-fine-grained Ni rich pseudoelastic NiTi wires studied by electrical resistance N2 - Temperature-induced, stress-induced martensitic phase transitions and martensite reorientation process in Ni rich (50.9 at.%) NiTi pseudoelastic NiTi wires with ultra-fine grained (UFG) microstructure were studied by electrical resistance measurements. Measurements of the electrical resistance as a function of temperature at different constant mechanical loads accompanied by complementary experiments with variable loads at constant temperature were performed. Results show that the transformation mechanisms in UFG microstructures exhibit a higher level of complexity when compared with those characterizing the behavior of other microstructures (e.g., recrystallized or larger grains size). It was found that a threshold stress level below 150 MPa delimits the transition from a homogeneous (low stress) to localized but reversible Lüders type transformation (high stress) when the transformations are induced under constant applied stress and that reorientation processes require stresses of 100 MPa in the present UFG wires. Even though the strain evolutions do not always show two distinct yielding events during cooling or heating, electrical resistance measurements proved that a two-step transformation involving R-phase and B19' martensite was always present in the extended range of temperatures and stresses investigated here. KW - Shape memory alloys KW - NiTi KW - Martensitic transformation KW - Electrical resistance PY - 2018 DO - https://doi.org/10.1016/j.jallcom.2017.12.009 SN - 0925-8388 VL - 735 SP - 2574 EP - 2583 PB - Elsevier AN - OPUS4-43549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Interaction of thermo-mechanical fatigue, creep and cyclic oxidation in 9-12% Cr steels N2 - In recent years, the performance of heat resistant ferritic-martensitic steels under cyclic oxidation and cyclic mechanical loading has gained considerable attention. The growing contributions of renewable energy sources to electricity generation have triggered a shift from continuous (baseload) operation of conventional power plants towards cyclic or “flexible” operation, which is needed to stabilize the electric grids by balancing the highly variable renewable’s input. Compared to the impressive amount of data on isothermal oxidation/corrosion and static mechanical loading (creep) that was compiled over decades, only little and sometimes contradictory information is so far available on the reaction of these alloys to cyclic conditions. The latter may involve frequent transients or holds at intermediate temperatures, as well as shut-downs and start-ups with high temperature rates which result in cyclic mechanical loads (thermo-mechanical fatigue, TMF) and thermo-cyclic oxidation at variable temperature. Our contribution will report on recent findings obtained within the framework of a junior research group which investigates the oxidation and fatigue of the ferritic-martensitic grades P91, P92 and VM12 SHC under thermo-cyclic conditions. Cyclic oxidation tests are carried out in steam using different sample shapes (flat coupons, U-segments and rings taken from heat exchanger tubes). Special attention is paid to changes in the kinetics and the integrity and possible delamination/spalling of the oxide layers. Mechanical tests are carried out on material from real steam pipes with a focus on the softening behaviour and lifetime issues resulting from combined creep/TMF loadings. All experiments are carried out in the 300-620°C regime with temperature and load profiles that resemble typical loading scenarios in power plants and are complemented by detailed microstructural characterisation. T2 - IUTAM-Symposium Multi-scale Fatigue, Fracture & Damage of Materials in Harsh Environments CY - Galway, Ireland DA - 28.08.2017 KW - Low cycle fatigue KW - Thermo-mechanical fatigue KW - Creep-fatigue KW - Steam oxidation KW - Power plants PY - 2017 AN - OPUS4-42654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbricht, Jürgen A1 - Lippmann, Tim A1 - Klingelhöffer, Hellmuth A1 - Rehmer, Birgit A1 - Skrotzki, Birgit T1 - Mechanical characterisation of heat resistant power plant materials by creep and fatigue testing in controlled gas atmospheres N2 - The continuing increase of steam parameters of fossil fuelled high efficiency power plants and new combustion concepts for the capture and storage of carbon dioxide lead to harsher service conditions for the components and structural materials of such facilities. The present work introduces a test concept that allows testing of candidate materials under simultaneous mechanical and corrosive loading. The material's reaction can be directly investigated under simulated temperature, load and corrosion conditions of modern installations. First results obtained for different heat resistant steels suggest a strong influence of the environmental medium on the fatigue and creep behaviour. Such findings complement the data that is available from the classical qualification process of the materials and may support the material selection for new power plant installations. N2 - Die weitere Erhöhung der Dampfparameter von hocheffizienten fossil befeuerten Kraftwerken sowie neue Verbrennungskonzepte zur Realisierung der Kohlendioxidabscheidung und -speicherung führen zu erschwerten Einsatzbedingungen für die Bauteile und Strukturwerkstoffe solcher Anlagen. Die vorliegende Arbeit stellt ein Prüfkonzept vor, das die Prüfung von Kandidatenwerkstoffen unter überlagerter mechanischer und korrosiver Beanspruchung ermöglicht. Die Werkstoffreaktion kann direkt unter den simulierten Temperatur-, Last- und Korrosionsbedingungen moderner Anlagen untersucht werden. Erste Ergebnisse für verschiedene warmfeste Stähle deuten auf einen erheblichen Einfluss des Umgebungsmediums auf das Ermüdungs- und Kriechverhalten hin. Solche Erkenntnisse ergänzen die aus den Qualifizierungsuntersuchungen der Werkstoffe verfügbaren Daten und können so die Werkstoffauswahl für neue Anlagen unterstützen. KW - Hocheffiziente Kraftwerke KW - Kohlendioxidabscheidung und -speicherung (CCS) KW - Warmfeste Stähle KW - Mechanische Eigenschaften KW - Korrosionsverhalten KW - High efficiency power plants KW - Carbon capture and storage (CCS) KW - Heat resistant steels KW - Mechanical properties KW - Corrosion behaviour PY - 2014 DO - https://doi.org/10.1002/mawe.201400185 SN - 0933-5137 SN - 1521-4052 VL - 45 IS - 1 SP - 5 EP - 14 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-30309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Winkelmann, Aimo T1 - Improving the precision of orientation measurements from technical materials via EBSD pattern matching N2 - We use pattern matching of experimental and dynamically simulated backscattered Kikuchi diffraction (BKD) patterns to increase the orientation precision of electron backscatter diffraction (EBSD) measurements. In order to quantify the improvement in orientation precision, we analyze the experimental distribution of the kernel average misorientation (KAM) angles. We find that for the same raw data, i.e. the same EBSD data acquisition time budget, the pattern matching approach improves the KAM resolution by an order of magnitude compared to orientation data delivered from the conventional Hough-transform based data analysis. This quantitative improvement enables us to interpret small orientation changes in plastically deformed materials which are hidden in noisy orientation data delivered from the reference EBSD system. As an application example, we analyze a ferritic-martensitic steel (P92) sample before and after low-cycle fatigue (LCF) loading (±0.3% strain) at 620 °C. Whereas the low precision of the EBSD orientation data from the manufacturer software does not allow a reliable discrimination of the gradually changing microstructure, we find very clear systematic differences of the local microstructure after the pattern matching orientation refinement of the initial, raw pattern data. For the investigated P92 sample, the KAM-angle histograms are well described by two log-normal distributions indicating the already tempered and the remaining and mostly untempered martensite. KW - Misorientation KW - Thermo-mechanical loading KW - Martensite KW - Log-normal distribution KW - Bimodal distribution PY - 2018 DO - https://doi.org/10.1016/j.actamat.2018.08.028 VL - 159 SP - 408 EP - 415 PB - Elsevier Ltd. AN - OPUS4-46454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Performance of 9-12%Cr steels under cyclic loading and cyclic oxidation conditions N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in power plants due to their excellent creep and oxidation resistance. The growing share of renewable energy sources in power generation forces many of these plants into more flexible operation with frequent load shifts or shutdowns. These cyclic operation profiles constitute a major lifetime issue. The present contribution reports on current findings obtained in a multidisciplinary project which combines cyclic mechanical and cyclic oxidation testing with detailed microstructural analyses. Mechanical analyses are carried out on P92 and P91 steel grades to give an overview of 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 (creep-fatigue interaction). Oxidation testing focuses on the grades P92 and VM12 with the intention of clarifying the impact of frequent passes through intermediate temperature levels on the kinetics of steam-side oxidation and the characteristics of the evolving oxide scales. An attempt is made to evaluate their composition, strength, integrity and adhesion after up to 250 temperature cycles. Flat coupons as well as curved tube sections are tested to assess the mutual influence of geometry on oxide scale integrity. Complementary microstructural investigations by scanning and transmission electron microscopy plus EBSD are used for phase identification and substrate/oxide interface characterisation. The evolutions of grain size and dislocation density under different test conditions are quantified. T2 - International Conference on Power Plant Operation & Flexibility CY - London, UK DA - 04.07.2018 KW - Ferritic-martensitic steels KW - Low cycle fatigue KW - Thermo-mechanical fatigue KW - Cyclic oxidation PY - 2018 AN - OPUS4-47115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Cyclic loading and creep-fatigue performance of P92 N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in power plants due to their excellent creep and oxidation resistance. The growing share of renewable energy sources in power generation forces many of these plants into more flexible operation with frequent load shifts or shutdowns. These cyclic operation profiles constitute a major lifetime issue. The present contribution reports on current findings obtained in a multidisciplinary project which combines cyclic mechanical and cyclic oxidation testing of different 9-12% Cr grades with detailed microstructural analyses. Mechanical analyses are carried out on P92 and P91 steel grades to give an overview of 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. Complementary microstructural investigations by scanning and transmission electron microscopy plus EBSD are used for phase identification, substrate/oxide interface characterization and quantification of the microstructure evolution under cyclic conditions. T2 - 44th MPA-Seminar CY - Leinfelden/Stuttgart, Germany DA - 17.10.2018 KW - Ferritic-martensitic steels KW - Fatigue KW - Creep-fatigue PY - 2018 AN - OPUS4-47116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Agudo Jácome, Leonardo A1 - Jürgens, Maria A1 - Roohbakhshan, Farshad A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Cyclic loading performance and related microstructure evolution of ferritic-martensitic 9-12% Cr steels 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. T2 - 44th MPA-Seminar CY - Leinfelden/Stuttgart, Germany DA - 17.10.2018 KW - Ferritic-martensitic steels KW - Cyclic loading KW - Microstructure evolution PY - 2018 SP - 259 EP - 265 AN - OPUS4-47118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klingelhöffer, Hellmuth A1 - Aegerter, J. A1 - Scherm, T. A1 - Schenuit, E. A1 - Sotheran, S. A1 - Loveday, M. A1 - Bosch, P. A1 - Bloching, H. A1 - Olbricht, Jürgen A1 - McEnteggart, I. T1 - Discussion on “Analysis on the issues in ISO 6892-1 and TENSTAND WP4 report based on the data of confirm tests by 21 laboratories” by H. Li, X. Zhou, J. Shen, and D. Luo. The regular article was published in journal of Testing and Evaluation, Vol. 45, No. 3, 2017, pp. 723–731, doi:10.1520/ JTE20150479. ISSN 0090-3973 N2 - The authors, Li et al., of the paper entitled “Analysis on the Issues in ISO 6892-1 and TENSTAND WP4 Report Based on Data to Confirm Tests by 21 Laboratories” (J. Test. Eval. DOI: 10.1520/JTE20150479 (online only)) have expressed views that the authors of this rebuttal believe to be based on fundamental misunderstandings and misinterpretations of the tensile testing standard ISO 6892-1:2009, ISO 6892-1:2016, and its former versions, thus leading to erroneous conclusions. This refutation is intended to clarify the understanding of ISO 6892-1 and to address the misunderstandings and the misinterpretations of the authors of the paper. The present standard ISO 6892-1:2016 has a long history dating back to the 1970s. At that time, the tensile testing procedure was standardized on the National and International scale in parallel. To understand the present standard, the knowledge of the history helps to understand the background of details of the testing procedure implemented today. The history of the tensile testing standard has been discussed extensively during the annual international standardization meeting of ISO committee TC 164 SC1 for the last few years, at which some of the authors of the Li et al. paper attended. The authors continue to disagree with facts that were agreed by the consortium of the European research project TENSTAND and by the present international experts involved in ISO TC 164 SC1. It appears that the principal objective of the authors regarding their present publication was to increase the testing speed during tensile testing. However, the international standardization community has previously declined similar proposals by some of the authors. Many Arguments presented by Li et al. were thus refuted. The conclusions of their paper are misleading and the international standardization community for tensile testing refused to revise the present standard, ISO 6892-1 (2016), according the authors’ proposals. KW - Tnsile testing KW - ISO 6892-1 KW - TENSTAND WP4 Report PY - 2017 UR - www.astm.org DO - https://doi.org/10.1520/JTE20160526 SN - 0090-3973 VL - 45 IS - 3 SP - 1105 EP - 1114 PB - ASTM CY - West Conshohocken, PA, USA AN - OPUS4-46690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Low Cycle Fatigue and Relaxation Performance of Ferritic–Martensitic Grade P92 Steel N2 - Due to their excellent creep resistance and good oxidation resistance, 9–12% Cr ferritic–martensitic stainless steels are widely used as high temperature construction materials in power plants. However, the mutual combination of different loadings (e.g., creep and fatigue), due to a “flexible” operation of power plants, may seriously reduce the lifetimes of the respective components. In the present study, low cycle fatigue (LCF) and relaxation fatigue (RF) tests performed on grade P92 helped to understand the behavior of ferritic–martensitic steels under a combined loading. The softening and lifetime behavior strongly depend on the temperature and total strain range. Especially at small strain amplitudes, the lifetime is seriously reduced when adding a hold time which indicates the importance of considering technically relevant small strains. KW - Ferritic–martensitic steel KW - P92 KW - Low cycle fatigue KW - Relaxation fatigue KW - Cyclic softening PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473905 DO - https://doi.org/10.3390/met9010099 VL - 9 IS - 1 SP - 99, 1 EP - 25 PB - MDPI AN - OPUS4-47390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen A1 - Kühn, Hans-Joachim ED - Schmauder, S. ED - Chawla, K. K. ED - Chawla, N. ED - Chen, W. ED - Kagawa, Y. T1 - High temperature mechanical testing of metals N2 - Performing mechanical tests at high temperatures is a nontrivial issue: Compared to room temperature testing, additional phenomena like time-dependent Deformation processes and oxidation effects raise the complexity of the material’s response, while more sophisticated test setups and additional control parameters increase the number of potential sources of error. To a large extent, these complications can be overcome by carefully following all recommendations given in the respective high temperature testing standards, but more comprehensive background information helps to identify points of specific importance in particular test campaigns. In this chapter, an overview is given on general high temperature testing issues like the appropriate choice of experimental equipment and key aspects of temperature measurement. In subsequent sections, the major static and dynamic high temperature test methods are reviewed and their Special features, as compared to testing at room temperature, are highlighted based on example data sets. Influences of specimen size and environmental effects are shortly outlined in a concluding section. In the whole chapter, a focus is set on testing of “classical” metallic high temperature materials, but many considerations are equally valid for testing of intermetallics, composites, and high temperature ceramics. KW - Creep, Creep Rupture, and Stress Rupture KW - Relaxation tests KW - Low Cycle Fatigue (LCF) KW - Thermomechanical Fatigue (TMF) KW - Fatigue crack propagation PY - 2018 SN - 978-981-10-6855-3 DO - https://doi.org/10.1007/978-981-10-6855-3_44-1 SP - 1 EP - 38 PB - Springer Nature Singapore Pte Ltd. CY - Singapore AN - OPUS4-44349 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klingelhoeffer, Hellmuth A1 - Aegerter, J. A1 - Scherm, T. A1 - Schenuit, E. A1 - Sotheran, S. A1 - Loveday, M. A1 - Bosch, P. A1 - Bloching, H. A1 - Olbricht, Jürgen A1 - McEnteggart, I. T1 - Discussion on "Analysis on the issues in ISO 6892-1 and TENSTAND WP4 report based on the data of confirm tests by 21 laboratories" N2 - The authors, Li et al., of the paper entitled “Analysis on the Issues in ISO 6892-1 and TENSTAND WP4 Report Based on Data to Confirm Tests by 21 Laboratories” (J. Test. Eval. DOI: 10.1520/JTE20150479 (online only)) have expressed views that the authors of this rebuttal believe to be based on fundamental misunderstandings and misinterpretations of the tensile testing standard ISO 6892-1:2009, ISO 6892-1:2016, and its former versions, thus leading to erroneous conclusions. This refutation is intended to clarify the understanding of ISO 6892-1 and to address the misunderstandings and the misinterpretations of the authors of the paper. The present standard ISO 6892-1:2016 has a long history dating back to the 1970s. At that time, the tensile testing procedure was standardized on the National and International scale in parallel. To understand the present standard, the knowledge of the history helps to understand the background of details of the testing procedure implemented today. The history of the tensile testing standard has been discussed extensively during the annual international standardization meeting of ISO committee TC 164 SC1 for the last few years, at which some of the authors of the Li et al. paper attended. The authors continue to disagree with facts that were agreed by the consortium of the European research project TENSTAND and by the present international experts involved in ISO TC 164 SC1. It appears that the principal objective of the authors regarding their present publication was to increase the testing speed during tensile testing. However, the international standardization community has previously declined similar proposals by some of the authors. Many arguments presented by Li et al. were thus refuted. The conclusions of their paper are misleading and the international standardization community for tensile testing refused to revise the present standard, ISO 6892-1 (2016), according the authors’ proposals. KW - Tensile testing procedure KW - ISO 6892-1 KW - TENSTAND WP4 Final Report PY - 2017 DO - https://doi.org/10.1520/JTE20160526 SN - 0090-3973 SN - 1945-7553 VL - 45 IS - 3 SP - 1105 EP - 1114 PB - ASTM International CY - West Conshohocken, PA, USA AN - OPUS4-40267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Corrosion and fatigue under new operational conditions - BAM's facilities and current activities T2 - 10th Liège Conference on Materials for Advanced Power Engineering CY - Liège, Belgium DA - 2014-09-14 PY - 2014 AN - OPUS4-31407 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Size Effects in Miniature Specimen Creep Testing of P91 T2 - ECCC Creep & Fracture 2014 (3rd International ECCC Conference) CY - Rome, Italy DA - 2014-05-05 PY - 2014 AN - OPUS4-30713 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Size effects in miniature specimen creep testing of P91 N2 - The use of miniaturized specimen geometries in mechanical testing allows extracting the sample material directly from critical components of power plants like e.g. headers and pipes. In this way, both the impacts of the manufacture of the component (including all shaping and tempering influences) and of the complex aging/loading/oxidation conditions during Service can be analyzed and representative mechanical properties are obtained. In the present study, example results of a comparative creep and creep rupture study on P91 tempered martensite ferritic Steel, involving Standard and miniature specimens that were all taken from one batch of material, are presented. Cylindrical creep specimens with a minimum gauge length diameter of 3 mm were used, representing the smallest recommended test geometry of ISO 204. The test results of miniature specimens exhibit all characteristic creep features of tempered martensite ferritic steels, and analysis of the stress and temperature dependence of creep results in values that correspond well to literature data for P91. However, direct comparison with large scale specimen data reveals small but systematic variations in minimum creep rates, elongations at fracture and times to rupture. In our contribution, these differences are discussed in the light of literature findings on specimen size influences in other heat resistant alloys. Size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. T2 - 3rd International ECCC Creep & Fracture Conference 2014 CY - Rome, Italy DA - 05.05.2014 PY - 2014 SN - 978-88-7484-380-0 SP - Paper 43, 1 EP - 9 AN - OPUS4-30726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - FLEXIKON - Teil 2: Ermüdungsverhalten, Schädigungsentwicklung und Lebensdauer von 9-12% Cr-Stählen im zyklischen Kraftwerksbetrieb N2 - Schnelle Lastwechsel führen v.a. in dickwandigen Kraftwerksbauteilen zu starken thermischen und mechanischen Beanspruchungen, da sich hohe Temperaturgradienten über der Wand des Bauteils einstellen. Es ergeben sich komplexe Lastkollektive aus zeitlich veränderlichen Spannungen/Dehnungen und Temperaturen, die formal einer Kombination aus Kriechbeanspruchung, Kriechermüdung und thermomechanischer Ermüdung (TMF) entsprechen. T2 - 47. Kraftwerkstechnisches Kolloquium CY - Dresden DA - 13.10.2015 KW - TMF KW - LCF KW - P91 KW - P92 PY - 2015 AN - OPUS4-35613 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Development of TMF testing – a little look back N2 - This presentation shortly outlines the timescale on which thermal and thermo-mechanical fatigue have developed both in academic research and industry. T2 - 3rd International Workshop on Thermo-Mechanical Fatigue CY - Berlin, Germany DA - 27.04.2016 KW - History KW - Thermal fatigue/shock KW - Thermo-mechanical fatigue PY - 2016 AN - OPUS4-36055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Untersuchung der Werkstoffschädigung durch kombinierte thermo-mechanische und korrosive Beanspruchung in hocheffizienten Energiewandlungsanlagen T2 - DFG-Konferenz Perspektiven der Energieforschung, Rundgespräch "Werkstoffe in der Energietechnik" CY - Berlin, Germany DA - 2012-09-20 PY - 2012 AN - OPUS4-26551 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbricht, Jürgen A1 - Yawny, A. A1 - Pelegrina, J.L. A1 - Dlouhy, A. A1 - Eggeler, G. T1 - On the stress-induced formation of R-phase in ultra-fine-grained Ni-Rich NiTi shape memory alloys N2 - Phase transformations in binary ultra-fine-grained (UFG) pseudoelastic NiTi wires were studied in a wide temperature range using mechanical loading/unloading experiments, resistance measurements, differential scanning calorimetry (DSC), thermal infrared imaging, and transmission electron microscopy (TEM). The formation of R-phase can be detected in the mechanical experiments. It is shown that the stress-strain response of the R-phase can be isolated from the overall stress-strain data. The R-phase always forms prior to B19¢ when good pseudoelastic properties are observed. The stress-induced B2 to R-phase transition occurs in a homogeneous manner, contrary to the localized character of the B2/R to B19' transformations. The temperature dependence of the critical stress values for the formation of the martensitic phases shows a Clausius Clapeyron type of behavior with constants close to 6 MPa/K (B19') and 18 MPa/K (R-phase). A stress-temperature map is suggested that summarizes the experimentally observed sequences of elementary transformation/deformation processes. KW - Phase transformation KW - Shape memory KW - Pseudoelasticity KW - NiTi KW - R-phase PY - 2011 DO - https://doi.org/10.1007/s11661-011-0679-y SN - 1073-5623 SN - 1543-1940 VL - 42A IS - 9 SP - 2556 EP - 2574 PB - The Minerals, Metals and Materials Society CY - Warrendale AN - OPUS4-24968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Characterization of the creep properties of heat resistant 9-12% chromium steels by miniature specimen testing N2 - A miniature specimen geometry is presented that allows to extract small samples for tensile creep tests directly from critical components of steam generators in power plants like e.g. superheater tubes. In this way, material can be tested which has been subjected to the full processing chain of the component. The specimens then exhibit all microstructural modifications that are present in the component after the shaping process and heat treatment, and representative mechanical properties are determined. Similarly, specimens can be extracted from pre-corroded test pieces or used components after service to determine the impact of complex aging/loading/oxidation conditions during service on the mechanical properties of the material. The applicability of the miniature specimen test method is demonstrated in a comparative creep study involving standard and miniature specimens of P91 tempered martensite ferritic steel. Test results indicate satisfactory accuracy/repeatability of the method. Comparison with large scale specimen data reveals an influence of specimen size on the obtained creep behavior. These size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. KW - Fossil fuel power plants KW - Creep testing KW - Miniature specimen KW - Size effects KW - Tempered martensite ferritic steels KW - P91 PY - 2013 DO - https://doi.org/10.1016/j.msea.2013.07.067 SN - 0921-5093 SN - 1873-4936 VL - 585 SP - 335 EP - 342 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-29080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbricht, Jürgen A1 - Yawny, A. A1 - Pelegrina, J.L. A1 - Eggeler, G. A1 - Yardley, V. A. T1 - Characteristics of the stress-induced formation of R-phase in ultrafine-grained NiTi shape memory wire N2 - The transformation between the cubic B2 and monoclinic B19' phases in ultrafine-grained pseudoelastic NiTi can occur as a two-step process involving the intermediate rhombohedral R-phase. Experimental work using differential scanning calorimetry, electrical resistance measurements and transmission electron microscopy has demonstrated the formation of this intermediate phase during thermal cycling and during mechanical loading. In the present paper, complementary mechanical and thermographic results are presented which allow to further assess the character of the stress-induced R-phase formation. The transformation from B2 to R-phase is demonstrated to occur homogeneously within the gauge length rather than via advancing Lüders-type transition regions as it is the case in the localized transformation from B2 or R-phase to B19'. KW - NiTi shape memory alloys KW - Pseudoelasticity KW - Stress-induced phase transformations KW - Localization KW - R-phase PY - 2013 DO - https://doi.org/10.1016/j.jallcom.2013.06.056 SN - 0925-8388 SN - 1873-4669 VL - 579 SP - 249 EP - 252 PB - Elsevier B.V. AN - OPUS4-28833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schaefer, A. A1 - Wagner, M.F.-X. A1 - Pelegrina, J.L. A1 - Olbricht, Jürgen A1 - Eggeler, G. T1 - Localization events and microstructural evolution in ultra-fine grained NiTi shape memory alloys during thermo-mechanical loading N2 - Subjecting a thin NiTi specimen to uniaxial tension often leads to a localized martensitic transformation: macroscopic transformation bands form and propagate through the specimen, separating it into regions of fully transformed martensite and original austenite. In the present study, the alternating current potential drop (ACPD) technique is used to analyze the change in electrical resistance of ultra-fine grained NiTi wires subjected to a broad range of thermo-mechanical load cases: (i) uniaxial tensile straining at constant temperatures (pseudoelastic deformation); (ii) cooling and heating through the transformation range at constant load (actuator load case); (iii) a combination of mechanical and thermal loading. We monitor the ACPD signals in several zones along the gauge length of specimens, and we demonstrate that a localized type of transformation is a generic feature of pseudoelastic as well as of shape memory deformation. Moreover, the ACPD signals allow to differentiate between temperature-induced martensite (formed during cooling at no or relatively small loads), stress-induced martensite, and reoriented martensite (formed under load at low temperatures). PY - 2010 DO - https://doi.org/10.1002/adem.201000063 SN - 1438-1656 VL - 12 IS - 6 SP - 453 EP - 459 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-28616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Evolution of strengthening phases in applied metallic materials under external loads T2 - Kick-off-Meeting des Schwerpunktprogramms 1713 "Chemomechanik" der DFG CY - Bochum, Germany DA - 2013-05-27 PY - 2013 AN - OPUS4-28630 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bismarck, Marck A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Size effects in miniature specimen creep testing of P91 N2 - The use of miniaturized specimen geometries in mechanical testing allows extracting the sample material directly from critical components of power plants like e.g. headers and pipes. In this way, both the impacts of the manufacture of the component (including all shaping and tempering influences) and of the complex aging/loading/oxidation conditions during Service can be analyzed and representative mechanical properties are obtained. In the present study, example results of a comparative creep and creep rupture study on P91 tempered martensite ferritic Steel, involving Standard and miniature specimens that were all taken from one batch of material, are presented. Cylindrical creep specimens with a minimum gauge length diameter of 3 mm were used, representing the smallest recommended test geometry of ISO 204. The test results of miniature specimens exhibit all characteristic creep features of tempered martensite ferritic steels, and analysis of the stress and temperature dependence of creep results in values that correspond well to literature data for P91. However, direct comparison with large scale specimen data reveals small but systematic variations in minimum creep rates, elongations at fracture and times to rupture. In our contribution, these differences are discussed in the light of literature findings on specimen size influences in other heat resistant alloys. Size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. T2 - 3rd International ECCC Conference CY - Rom, Italy DA - 05.05.2014 KW - Material PY - 2017 SN - 978-88-7484-510-1 SP - 430 EP - 435 PB - Tipography Inail CY - Milan AN - OPUS4-41239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kingelhöffer, Hellmuth A1 - Affeldt, E. E. A1 - Bache, M. A1 - Bartsch, M. A1 - Beck, T. A1 - Christ, H. J. A1 - Fedelich, Bernard A1 - Hähner, P. A1 - Holdsworth, S. R. A1 - Lang, K.-H. A1 - McGaw, M. A1 - Olbricht, Jürgen A1 - Remy, L. A1 - Skrotzki, Birgit A1 - Stekovich, S. T1 - Editorial - Special issue: Recent developments in thermo-mechanical fatigue N2 - Components in the Aerospace, Power and Automotive engineering sectors are frequently subjected to cyclic stresses induced by thermal fluctuations and mechanical loads. For the design of such components, reliable material property data are required which need to be acquired using well accepted and reproducible test procedures for thermo-mechanical fatigue (TMF) loading. There is limited availability of proven TMF data indicating there is need for further research and testing. The TMF behaviour of materials is often desired to be simulated in models which describe the cyclic stress-strain behaviour, the fatigue life and the cyclic crack growth behaviour. There is a continuous need for the development and amendment of such models. Models can be validated by using materials in industrial applications which are subjected to TMF loading. The 3rd Workshop on Thermo-Mechanical Fatigue was held on 27–29 April 2016 at BAM, Berlin, Germany. The workshop was attended by 90 attendees coming from 17 countries in the world. 38 presentations including five poster presentations were held. The following topics were covered by the workshop: – TMF of materials coated with Thermal Barrier Coatings. – Thermal Gradient Mechanical Fatigue. – TMF crack growth. – TMF + High Cycle Fatigue. – TMF Modelling and Lifetime Prediction. – TMF Properties of steels, cast iron, Al-, Mg- and Ni-alloys – Advanced TMF Testing Techniques. – Industrial Applications. A panel discussion was held regarding the present state of TMF testing standards (ISO and ASTM) and their potential for improvement. The discussion and contributions were summarized and forwarded to the standard committees. The 3rd TMF-Workshop ensured the continuation of international exchange of knowledge providing a forum to present and discuss all recent developments in the field of thermo-mechanical fatigue. The current special issue publishes eleven selected papers of the 3rd TMF-Workshop 2016. The papers were peer reviewed by a number of experts in the Thermo-Mechanical Fatigue sector. I hope you will enjoy reading papers of this special issue. T2 - 3rd International Workshop on Thermo-Mechanical Fatigue (TMF-Workshop 2016) CY - Berlin, Germany DA - 27.04.2016 KW - Fatigue damage KW - Thermo-mechanical fatigue KW - Fatigue life time KW - Life time prediction KW - TMF PY - 2017 DO - https://doi.org/10.1016/j.ijfatigue.2017.02.002 SN - 0142-1123 VL - 99 IS - 2 SP - 215 PB - Elsevier CY - Oxford AN - OPUS4-40895 LA - eng 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 - 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 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 - JOUR A1 - Jürgens, Maria A1 - Sonntag, Nadja A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - The effect of dwell times on the thermomechanical fatigue life performance of grade P92 steel at intermediate and low strain amplitudes N2 - Results of an extended TMF test program on grade P92 steel in the temperature range of 620 °C - 300 °C, comprising in-phase (IP) and out-of-phase (OP) tests, partly performed with symmetric dwells at Tmax/Tmin, are presented. In contrast to previous studies, the low-strain regime is also illuminated, which approaches flexible operation in a power plant with start/stop cycles. At all strain amplitudes, the material performance is characterized by continuous cyclic softening, which is retarded in tests at lower strains but reaches similar magnitudes in the course of testing. In the investigated temperature range, the phase angle does not affect fatigue life in continuous experiments, whereas the IP condition is more detrimental in tests with dwells. Fractographic analyses indicate creep-dominated and fatigue-dominated damage for IP and OP, respectively. Analyses of the (micro)hardness distribution in the tested specimens suggest an enhanced microstructural softening in tests with dwell times for the low- but not for the high-strain regime. To rationalize the obtained fatigue data, the fracture-mechanics-based D_TMF concept, which was developed for TMF life assessment of ductile alloys, was applied. It is found that the D_TMF parameter correlates well with the measured fatigue lives, suggesting that subcritical growth of cracks (with sizes from a few microns to a few millimeters) governs failure in the investigated range of strain amplitudes. KW - 9-12%Cr steel KW - Thermomechanical fatigue KW - Symmetric dwell periods KW - Low strain KW - Parametric modeling PY - 2021 DO - https://doi.org/10.1016/j.msea.2020.140593 VL - 805 SP - 140593 PB - Elsevier B.V. AN - OPUS4-52374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Jürgens, Maria A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Creep-fatigue of P92 in service-like tests with combined stress- and strain-controlled dwell times N2 - Complex service-like relaxation- and creep-fatigue tests with strain- and stress-controlled dwells and fatigue cycle durations of approx. 2200 s were performed exemplarily on a grade P92 steel at 620 ◦C in this study. The results indicate deviations in the prevailing creep mechanisms of long-term relaxation and creep dwells, affecting subsequent dwells, load shifts, and the macroscopic softening behavior quite differently. In addition, fracture surfaces and longitudinal metallographic sections reveal intergranular crack growth for complex loading with stress-controlled dwells, whereas complex strain-controlled tests enhance oxidation and transgranular crack propagation. These findings substantiate the limited transferability of relaxation-fatigue to creep-fatigue conditions. KW - Tempered martensite-ferritic steel KW - P92 KW - Dwell periods KW - Creep-fatigue interaction KW - Stress relaxation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564239 DO - https://doi.org/10.1016/j.ijfatigue.2022.107381 SN - 0142-1123 VL - 168 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-56423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Sonntag, Nadja A1 - Jürgens, M. A1 - Uhlemann, Patrick A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Datasets for Service-Like Creep-Fatigue Experiments on Grade P92 Steel N2 - The dataset contains experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Further information on data and data acquisition, analysis, and experimental details are given in “Experimental Data from Service-Like Creep-Fatigue Experiments on Grade P92 Steel”, submitted to Data in Brief. Additional analyses of these datasets, as well as experimental findings and discussions are presented in “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times”, submitted to International Journal of Fatigue. KW - Creep-fatigue KW - Stress relaxation KW - Dwell-Fatigue KW - Tempered martensite-ferritic steel PY - 2022 DO - https://doi.org/10.5281/zenodo.7198218 PB - Zenodo CY - Geneva AN - OPUS4-55995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chen, Yue A1 - Schilling, Markus A1 - von Hartrott, P. A1 - Beygi Nasrabadi, Hossein A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Ontopanel: A Tool for Domain Experts Facilitating Visual Ontology Development and Mapping for FAIR Data Sharing in Materials Testing N2 - In recent years, the design and development of materials are strongly interconnected with the development of digital technologies. In this respect, efficient data management is the building block of material digitization and, in the field of materials science and engineering (MSE), effective solutions for data standardization and sharing of different digital resources are needed. Therefore, ontologies are applied that represent a map of MSE concepts and relationships between them. Among different ontology development approaches, graphical editing based on standard conceptual modeling languages is increasingly used due to its intuitiveness and simplicity. This approach is also adopted by the Materials-open-Laboratory project (Mat-o-Lab), which aims to develop domain ontologies and method graphs in accordance with testing standards in the field of MSE. To suit the actual demands of domain experts in the project, Ontopanel was created as a plugin for the popular open-source graphical editor diagrams.net to enable graphical ontology editing. It includes a set of pipeline tools to foster ontology development in diagrams.net, comprising imports and reusage of ontologies, converting diagrams to Web Ontology Language (OWL), verifying diagrams using OWL rules, and mapping data. It reduces learning costs by eliminating the need for domain experts to switch between various tools. Brinell hardness testing is chosen in this study as a use case to demonstrate the utilization of Ontopanel. KW - Materials Testing KW - Ontology KW - Visual ontology development KW - Data mapping KW - FAIR PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560339 DO - https://doi.org/10.1007/s40192-022-00279-y SP - 1 EP - 12 PB - Springer AN - OPUS4-56033 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayerlein, Bernd A1 - Hanke, T. A1 - Muth, Thilo A1 - Riedel, Jens A1 - Schilling, Markus A1 - Schweizer, C. A1 - Skrotzki, Birgit A1 - Todor, A. A1 - Moreno Torres, Benjami A1 - Unger, Jörg F. A1 - Völker, Christoph A1 - Olbricht, Jürgen T1 - A Perspective on Digital Knowledge Representation in Materials Science and Engineering N2 - The amount of data generated worldwide is constantly increasing. These data come from a wide variety of sources and systems, are processed differently, have a multitude of formats, and are stored in an untraceable and unstructured manner, predominantly in natural language in data silos. This problem can be equally applied to the heterogeneous research data from materials science and engineering. In this domain, ways and solutions are increasingly being generated to smartly link material data together with their contextual information in a uniform and well-structured manner on platforms, thus making them discoverable, retrievable, and reusable for research and industry. Ontologies play a key role in this context. They enable the sustainable representation of expert knowledge and the semantically structured filling of databases with computer-processable data triples. In this perspective article, we present the project initiative Materials-open-Laboratory (Mat-o-Lab) that aims to provide a collaborative environment for domain experts to digitize their research results and processes and make them fit for data-driven materials research and development. The overarching challenge is to generate connection points to further link data from other domains to harness the promised potential of big materials data and harvest new knowledge. KW - Data infrastructures KW - Digital representations KW - Digital workflows KW - Knowledge graphs KW - Materials informatics KW - Ontologies KW - Vocabulary providers PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546729 DO - https://doi.org/10.1002/adem.202101176 SN - 1438-1656 SP - 1 EP - 14 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-54672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mosquera Feijoo, Maria A1 - Oder, Gabriele A1 - Saliwan Neumann, Romeo A1 - Buchheim, Michaela A1 - Kranzmann, Axel A1 - Olbricht, Jürgen T1 - Impact of Sample Geometry and Surface Finish on VM12‑SHC Ferritic–Martensitic Steel Under Cyclic Steam Atmosphere Operating Conditions N2 - The steam side oxidation of ferritic–martensitic VM12-SHC steel was investigated under thermo-cyclic conditions in water steam at 620/320 °C and 30 bar with a focus on assessing the influence of pre-oxidation time, specimen geometry and surface finish. The specimens were pre-oxidized under isothermal conditions in water steam at 620 °C and 30 bar for 500 h or 1500 h. After pre-oxidation treatment, all specimens were subjected up to 258 thermal cycles. Three different geometries—rectangular coupons, U-shaped ring segments and ring samples—were investigated to evaluate the influence of open/closed shape, and flat/curved surface on corrosion rate. At the same time, two types of surface finish were considered: “as received” and “ground.” The formation of a protective scale by pre-oxidation was investigated. EBSD and ESMA analyses revealed that the Cr-content of the alloy appeared to be insufficient for obtaining a protective oxide scale under studied conditions, at the same time the anayses confirmed that initial oxidation depends on presence of minor alloying elements as Si and Mn, strong oxide formers which can alter the kinetics and morphology of the corrosion reaction. Moreover, rectangular coupons with small wall thickness and flat surface exhibited the highest corrosion rate, while “ground” curved samples showed only local oxidation. This indicates that for same pre-oxidation time, oxidation kinetics is controlled by curvature. KW - Cyclic steam oxidation KW - 12%Cr steel KW - Specimen geometry KW - Surface treatments PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551808 DO - https://doi.org/10.1007/s11085-022-10114-6 SN - 0030-770X SP - 1 EP - 18 PB - Springer AN - OPUS4-55180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Marschall, Niklas A1 - Bayerlein, Bernd A1 - Chen, Yue A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit A1 - von Hartrott, P. A1 - Portella, Pedro Dolabella A1 - Waitelonis, J. A1 - Birkholz, H. A1 - Grundmann, J. ED - Zimmermann, M. T1 - Zugversuchsdaten FAIR integriert: Von einer normenkonformen Ontologie bis zu interoperablen Daten im Triple Store N2 - Das hochaktuelle Thema der Integration und Wiederverwendung von Wissen und Daten aus Herstellung, Bearbeitung und Charakterisierung von Materialien ('Digitalisierung von Materialien') wird in den Projekten Innovationsplattform MaterialDigital (PMD, materialdigital.de) und Materials-open-Lab (Mat-o-Lab, matolab.org) adressiert. In diesem Beitrag werden die Weiterentwicklungen in diesen Projekten hinsichtlich der Speicherung von Zugversuchsdaten gemäß einer normenkonformen (DIN EN ISO 6892-1:2019-11) ontologischen Repräsentation vorgestellt. Das umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verknüpfung von Ontologie und Daten. Letztendlich können die entsprechenden Daten in einem Triple Store abgelegt und abgefragt werden. T2 - Werkstoffprüfung 2022 CY - Dresden, Germany DA - 27.10.2022 KW - Ontology KW - Semantic Web KW - Digitalization KW - Knowledge Representation KW - Tensile Test PY - 2022 UR - https://dgm.de/fileadmin/DGM/Veranstaltungen/2022/Werkstoffpruefung/Tagungsband/WP2022-Tagungsband-online.pdf SN - 978-3-88355-430-3 SP - 105 EP - 110 PB - DGM - Deutsche Gesellschaft für Materialkunde e.V CY - Sankt Augustin AN - OPUS4-56836 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Jürgens, Maria A1 - Uhlemann, Patrick A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Experimental data from service-like creep-fatigue experiments on grade P92 steel N2 - This article refers to the research article entitled “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times” [1]. It presents experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Such service-like (SL) tests with additional long-term stress- and strain-controlled dwell times are non-standard, rare, and expensive, making these data very valuable. They may be used to approximate cyclic softening in the technically relevant range, for the design of complex SL experiments, or for detailed analyses of stress-strain hystereses (e.g., for stress or strain partitioning methods, for the determination of hysteresis energies (work), inelastic strain components, etc.). In addition, the latter analyses may supply important input for advanced parametric lifetime modeling of components under creep-fatigue loading or model calibration parameters. KW - Tempered martensite-ferritic steel KW - Creep KW - Stress relaxation KW - Creep-fatigue KW - Dwell times PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578407 DO - https://doi.org/10.1016/j.dib.2023.109333 SN - 2352-3409 VL - 49 SP - 1 EP - 9 PB - Elsevier Inc. AN - OPUS4-57840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhadeliya, Ashok A1 - Rehmer, Birgit A1 - Fedelich, Bernard A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit A1 - Jokisch, T. ED - Zimmermann, M. T1 - Rissfortschrittsuntersuchungen an gefügten Nickelbasiswerkstoffen bei hoher Temperatur N2 - In nickelbasierten Superlegierungen, die für Gasturbinenschaufeln verwendet werden, sind bei hohen Betriebstemperaturen und -belastungen Kriechschäden, Ermüdung, Korrosion und Oxi-dation zu beobachten. Die betroffenen Turbinenschaufeln müssen ersetzt oder repariert werden, um Effizienzverluste und ein eventuelles Bauteilversagen zu vermeiden. In letzter Zeit wurden additive Fertigungs- und Lötverfahren für die Reparatur und das Fügen von Nickelbasiswerk-stoffen entwickelt, um die Einschränkungen der traditionellen Reparaturverfahren zu überwinden. Für eine auslegungsrelevante Bewertung des Risswachstumsverhaltens in den Fügezonen, die durch diese neuen Technologien erzeugt werden, sind Rissfortschrittsuntersuchungen erfor-derlich. Entsprechende Untersuchungen an gefügten Proben werden in diesem Beitrag vorge-stellt. Die Rissfortschrittsversuche werden an gefügten SEN-Proben (Single Edge Notch) bei einem Spannungsverhältnis von 0,1 und einer Temperatur von 950 °C durchgeführt. Das Riss-wachstum wird mit der DCPD-Methode (Direct Current Potential Drop) überwacht, und die ge-messenen Potenzialsignale werden anhand der optisch vermessenen Risslänge und einer Finite-Elemente-Analyse kalibriert. Der Spannungsintensitätsfaktor (SIF) für die gefügte SEN-Geometrie wird mit Hilfe von Finite-Elemente-Analysen berechnet. Auf diese Weise können Rissfortschrittskurven aus den experimentellen Daten abgeleitet werden. T2 - Tagung „Werkstoffprüfung 2022“ CY - Dresden, Germany DA - 27.10.2022 KW - Lötverbindung KW - Rissfortschritt KW - SEN-Probe KW - Gefügte Nickelbasislegierungen PY - 2022 SN - 978-3-88355-430-3 VL - 2022 SP - 67 EP - 72 AN - OPUS4-57090 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Einfluss von Haltezeiten auf die TMF-Lebensdauer von P92 bei mittleren und geringen Dehnungsamplituden N2 - Results of an extended TMF test program on grade P92 steel in the temperature range of 620 ◦C–300 ◦C, comprising in-phase (IP) and out-of-phase (OP) tests, partly performed with symmetric dwells at Tmax/Tmin, are presented. In contrast to previous studies, the low-strain regime is also illuminated, which approaches flexible operation in a power plant with start/stop cycles. At all strain amplitudes, the material performance is characterized by continuous cyclic softening, which is retarded in tests at lower strains but reaches similar magnitudes in the course of testing. In the investigated temperature range, the phase angle does not affect fatigue life in continuous experiments, whereas the IP condition is more detrimental in tests with dwells. Fractographic analyses indicate creep-dominated and fatigue-dominated damage for IP and OP, respectively. Analyses of the (micro)hardness distribution in the tested specimens suggest an enhanced microstructural softening in tests with dwell times for the low- but not for the high-strain regime. To rationalize the obtained fatigue data, the fracturemechanics-based DTMF concept, which was developed for TMF life assessment of ductile alloys, was applied. It is found that the DTMF parameter correlates well with the measured fatigue lives, suggesting that subcritical growth of cracks (with sizes from a few microns to a few millimeters) governs failure in the investigated range of strain amplitudes. T2 - DVM-Arbeitskreis Bauteilverhalten bei thermomechanischer Ermüdung - Workshop 2023 CY - Berlin, Germany DA - 20.09.2023 KW - 9–12%Cr steel KW - Thermomechanical fatigue KW - Symmetric dwell periods KW - Parametric modeling PY - 2023 AN - OPUS4-58431 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis Alexander A1 - Hammerschmidt, T. A1 - Gedsun, A. A1 - Forti, M. A1 - Olbricht, Jürgen A1 - Stotzka, R. A1 - Skrotzki, Birgit T1 - IUC02 Framework for Curation and Distribution of Reference Datasets using Creep Data of Ni-Base Superalloys as an Example N2 - In our current view, reference datasets in the MSE domain represent specific material properties, e.g., structural, mechanical, … characteristics. A reference dataset must fulfill high-quality standards, not only in precision of measurement but also in a comprehensive documentation of material, processing, and testing history (metadata). This Infrastructure Use Case (IUC) aims to develop a framework for generating reference material datasets using creep data of a single crystal Ni-based superalloy as a best practice example. In a community-driven process, we aim to encourage the discussion and establish a framework for the creation and distribution of reference material datasets. In this poster presentation, we highlight our current vision and activities and intend to stimulate the discussion about the topic reference datasets and future collaborations and work. T2 - NFDI-MatWerk Conference CY - Siegburg, Germany DA - 27.06.2023 KW - Referenzdaten KW - Reference data KW - Syngle Crystal alloy KW - Creep KW - Metadata schema PY - 2023 AN - OPUS4-57923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhadeliya, Ashok A1 - Rehmer, Birgit A1 - Fedelich, Bernard A1 - Jokisch, Torsten A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - High Temperature Fatigue Crack Growth in Nickel-Based Alloys Refurbished by Additive Manufacturing N2 - Hybrid additive manufacturing plays a crucial role in the restoration of gas turbine blades, where, e.g., the damaged blade tip is reconstructed by the additive manufacturing process on the existing blade made of a parent nickel-based alloy. However, inherent process-related defects in additively manufactured material, along with the interface created between the additively manufactured and the cast base material, impact the fatigue crack growth behavior in bi-material components. This study investigates the fatigue crack growth behavior in bi-material specimens of nickel-based alloys, specifically, additively manufactured STAL15 and cast alloy 247DS. The tests were conducted at 950 °C with stress ratios of 0.1 and −1. Metallographic and fractographic investigations were carried out to understand crack growth mechanisms. The results revealed significant retardation in crack growth at the interface. This study highlights the potential contributions of residual stresses and microstructural differences to the observed crack growth retardation phenomenon, along with the conclusion from an earlier study on the effect of yield strength mismatch on crack growth behavior at a perpendicular interface in bi-material specimens. T2 - Superalloys 2024 Conference CY - Champion, Pennsylvania, USA DA - 08.09.2024 KW - Fatigue crack growth KW - Bi-material structure KW - Additive manufacturing KW - Nickel-based alloys PY - 2024 SN - 978-3-031-63937-1 DO - https://doi.org/10.1007/978-3-031-63937-1_92 SN - 2367-1181 SN - 2367-1696 VL - 15th SP - 994 EP - 1001 PB - Springer CY - Cham AN - OPUS4-60907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhadeliya, Ashok A1 - Rehmer, Birgit A1 - Fedelich, Bernard A1 - Jokisch, T. A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Fatigue and fracture in dual-material specimens of nickel-based alloys fabricated by hybrid additive manufacturing N2 - The integration of additive manufacturing with traditional processes, termed hybrid additive manufacturing, has expanded its application domain, particularly in the repair of gas turbine blade tips. However, process-related defects in additively manufactured materials, interface formation, and material property mismatches in dual-material structures can significantly impact the fatigue performance of components. This investigation examines the low cycle fatigue and fatigue crack growth behaviors in dual-material specimens of nickel-based alloys, specifically the additively manufactured STAL15 and the cast alloy 247DS, at elevated temperatures. Low cycle fatigue experiments were conducted at temperatures of 950 °C and 1000 °C under a range of strain levels (0.3%–0.8%) and fatigue crack growth tests were conducted at 950 °C with stress ratios of 0.1 and −1. Fractographic and microscopic analyses were performed to comprehend fatigue crack initiation and crack growth mechanisms in the dual-material structure. The results consistently indicated crack initiation and fatigue fracture in the additively manufactured STAL15 material. Notably, fatigue crack growth retardation was observed near the interface when the crack extended from the additively manufactured STAL15 material to the perpendicularly positioned interface. This study highlights the importance of considering yield strength mismatch, as well as the potential effects of residual stresses and grain structure differences, in the interpretation of fatigue crack growth behavior at the interface. KW - Hybrid additive manufacturing KW - Dual-material nickel-based alloys KW - High-temperature fatigue crack growth KW - Low cycle fatigue PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609340 DO - https://doi.org/10.1016/j.jmrt.2024.08.211 SN - 2238-7854 VL - 32 SP - 3737 EP - 3749 PB - Elsevier B.V. AN - OPUS4-60934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Fedelich, Bernard A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Thermo-mechanical fatigue behavior of P91/P92 N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in power plants due to their excellent creep resistance and good oxidation resistance. Creep resistance is considered as the primary parameter in material selection for base-load power plants, but the growing share of renewable energy sources in power generation forces many installations into more "flexible" operation with frequent load reductions and shutdowns. Under cyclic operation of power plants, temperature gradients occur especially in thick-walled components. Locally, these gradients lead to complex time- and temperature-dependent loading scenarios which may result in superimposed creep deformation/damage, creep-fatigue and thermo-mechanical fatigue. The combination of different damage processes may seriously reduce the lifetimes of respective components. A fundamental understanding of the damage evolution in ferritic-martensitic steels under combined static and cyclic loading is therefore required. In the present contribution, the thermo-mechanical fatigue and creep-fatigue behavior of two different 9% Cr steel grades (P91 and P92) was investigated. Standard LCF/TMF-tests as well as near-service loading tests with different hold times have been carried out to study the material behavior of the new loading scenarios. Microstructural investigations help to identify the observed deformation characteristics (like e.g. pronounced softening) and the dominating damage mechanisms under different loads. The test programme is complemented by selected tests on service-aged material which demonstrate possible reactions of older components in existing plants to changes in operation profiles. In a next step, the experimental results will be used for parameter identification of a deformation and lifetime model to predict the material behavior. T2 - LCF08 CY - Dresden, Germany DA - 27.06.2017 KW - Near-service testing KW - Power plant KW - Ferritic-martensitic steels KW - P91 KW - P92 KW - Thermo-Mechanical Fatigue PY - 2017 SN - 978-3-9814516-5-8 VL - 2017 SP - 101 EP - 105 PB - DVM CY - Berlin AN - OPUS4-42268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -