Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-1088 Beitrag zu einem Tagungsband Müller, Karsten; Schriever, Sina; Wossidlo, Peter; Hamann, Andreas; Löwe, Peter Bruchmechanische Untersuchungen von Gusseisen mit Kugelgraphit bei Stoss- und Schlagbiege-Beanspruchung Berlin DVM Deutscher Verband für Materialforschung und -prüfung / Arbeitskreis Bruchvorgänge 2001 33. Tagung des DVM-Arbeitskreises Bruchvorgänge (DVM-Bericht 233) 33. Tagung des DVM-Arbeitskreises Bruchvorgänge Paderborn, Deutschland 2001-02-20 2001-02-21 233 267 274 2016-02-19 OPUS4-24932 Beitrag zu einem Tagungsband Häcker, Ralf; Klinger, Christian; Kahlcke, Ole; Schriever, Sina Grellmann, W. Zwischen Zeitstand und Relaxation - Einfluss der Proben- und Prüfmaschinensteifigkeit auf die Lebensdauer unter konstanter Belastung Zur Abschätzung der Lebensdauer eines bei höherer Temperatur langzeitbelasteten Bauteils wurden Zeitstandversuche, Relaxationsversuche und weitere Versuche mit unterschiedlichen Umgebungssteifigkeiten durchgeführt. Die Zeitstandversuche, deren Versuchsführung eine unendlich niedrige Umgebungssteifigkeit simuliert, liefern geringere Lebensdauern (Bruchzeiten) im Vergleich zu Versuchen mit endlich hohen, technisch relevanten Steifigkeiten bei vergleichbarer Probensteifigkeit (Geometrie), wobei die Lebensdauern mit steigender Umgebungssteifigkeit zunehmen. Die längsten Lebensdauern zeigen Relaxationsversuche mit einer unendlich hohen Umgebungssteifigkeit aufgrund ihrer Versuchsregelung. Für die Übertragung der an Proben gewonnenen Ergebnisse auf das Bauteil wurde das Steifigkeitsverhältnis Z zwischen der Steifigkeit der 'Probe' und der der 'Umgebung' definiert und angewandt. Das Steifigkeitsverhältnis des kritischen Bereichs im Bauteil und das der Werkstoffprobe in der Prüfmaschine sollten möglichst ähnlich sein. Dann lassen sich bei der Übertragung auf das Bauteil realistisch höhere Lebensdauern abschätzen als nur mit Kenntnis der Ergebnisse der Zeit-standversuche. Deutscher Verband für Materialforschung und -prüfung e.V. (DVM) 2011 DVM-Tagung Werkstoffprüfung 2011 - Neue Entwicklungen in der Werkstoffprüfung - Herausforderungen an die Kennwertermittlung 978-3-9814516-1-0 DVM-Tagung Werkstoffprüfung 2011 - Neue Entwicklungen in der Werkstoffprüfung - Herausforderungen an die Kennwertermittlung Berlin, Germany 01.12.2011 02.12.2011 643 267 272 2016-02-19 OPUS4-53937 Zeitschriftenartikel Ávila Calderón, Luis Alexander; Rehmer, Birgit; Schriever, Sina; Ulbricht, Alexander; Agudo Jácome, Leonardo; Sommer, Konstantin; Mohr, Gunther; Skrotzki, Birgit; Evans, Alexander Creep and creep damage behavior of stainless steel 316L manufactured by laser powder bed fusion This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism. Elsevier B.V. 2022 Materials Science and Engineering: A 830 142223 urn:nbn:de:kobv:b43-539373 10.1016/j.msea.2021.142223 https://creativecommons.org/licenses/by/4.0/deed.de 2021-12-08 OPUS4-52970 Forschungsdatensatz Skrotzki, Birgit; Schriever, Sina BAM reference data - Results of ASTM E139-11 creep tests on a reference material of Nimonic 75 nickel-base alloy Results of creep tests on a certified reference material at T = 600°C and a tensile creep load of 160 MPa are provided. The evaluated results include the times to reach 2% and 4% creep strain, respectively, and the creep rate after 400 h. The data were audited and are BAM reference data. Geneva Zenodo Bundesanstalt für Materialforschung und -prüfung (BAM) 2021 10.5281/zenodo.5106606 https://creativecommons.org/licenses/by/4.0/deed.de 2021-08-03 OPUS4-53132 Zeitschriftenartikel Epishin, A. I.; Fedelich, Bernard; Viguier, B.; Schriever, Sina; Svetlov, I. L.; Petrushin, N. V.; Saillard, R.; Proietti, A.; Poquillon, D.; Chyrkin, A. Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′ -phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 〈011〉{111} octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′ -reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2 〈011〉 mobile dislocations and knitting of new networks. Amsterdam Elsevier 2021 Materials Science & Engineering A 825 1 13 10.1016/j.msea.2021.141880 2021-08-24 OPUS4-44604 Beitrag zu einem Tagungsband Rockenhäuser, Christian; von Hartrott, P.; Metzger, M.; Schriever, Sina; Augenstein, E.; Karlin, J.; Piesker, Benjamin; Schweizer, Ch.; Skrotzki, Birgit Lebensdauerberechnung von Aluminium-Radialverdichterrädern unter Berücksichtigung der Werkstoffalterung In this project, a procedure was developed to improve the lifetime assessment precision of exhaust turbo charger radial compressor wheels made from the age hardenable aluminum alloy EN AW-2618A. This comprises particularly the consideration of material aging, which has to be anticipated during operation of such components under relevant service conditions (temperature, time, stress). First of all, a solid experimental database was established for the investigated material. This includes a mechanical as well as a microstructural characterization of the as-received state (T61) and after aging up to 25,000 h at relevant service temperatures (160 °C, 180 °C, 190 °C). The microstructural investigations focused on the development of the radii of the cylindrical hardening phase, which coarsens during aging. The relation between aging temperature, time and mechanical load (if applicable) was established for the first time to this extent. An interrelationship to describe the coarsening was established. The effect of aging on hardness, strength, creep behavior and fatigue lifetime (LCF, TMF) was studied and a correlation to the microstructure was established. The results of the creep tests were used to calibrate a modified hyperbolic sine creep model. A time and temperature dependent deformation model according to Chaboche, which describes the relevant phenomena of high temperature deformation and cyclic plasticity, was extended. It now considers material aging by describing the strength not only as a function of temperature but also as a function of aging, i.e. of the mean radius of the precipitates. A similar procedure was applied to extend the model in order to assess the fatigue lifetime. The calculated lifetimes of LCF and TMF tests completed during this project match well with the experimental results. Only one LCF test with a hold time of 900 s in tension deviates clearly from the mean value and shows the limits of the time independent damage model. Tests with shorter hold times of 60 s are within the scatter band, likewise the different aging conditions. A damage accumulation model additionally describing the progressive aging during lifetime was developed and implemented. Besides considering aging in the deformation and lifetime assessment, it is also possible to judge complex loading cycles in a postprocessing by rain flow classification of typical complex loading cycles. The methodology and the models were implemented into the Finite-Element software Abaqus and Ansys and are available for numerical assessment of components. 2018 Tagungsband R583 FVV Frühjahrstagung 2018 FVV Frühjahrstagung 2018 Bad Neuenahr, Germany 22.03.2018 97 130 2018-04-04 OPUS4-45284 Beitrag zu einem Tagungsband von Hartrott, P.; Rockenhäuser, Christian; Schriever, Sina; Skrotzki, Birgit Correlation of the precipitate size evolution and the creep rate of the aluminium alloy EN AW 2618A at 190 °C A short description of the work done on the topic "Correlation of the precipitate size evolution and the creep rate of the aluminium alloy EN AW 2618A at 190 °C" is given. 2018 Proceedings of the International Conference on Aluminium Alloys 16 978-1-926872-41-4 International Conference on Aluminium Alloys 16 Montreal, Canada 17.06.2018 99 2018-07-09 OPUS4-44090 Zeitschriftenartikel Rockenhäuser, Christian; Schriever, Sina; von Hartrott, P.; Piesker, Benjamin; Skrotzki, Birgit Comparison of long-term radii evolution of the S-phase in aluminum alloy 2618A during ageing and creep A study was made on the effect of creep loading on the precipitate radii evolution of the aluminum alloy 2618A. The overageing process of the alloy was investigated under load at a temperature of 190 °C with stresses between 79 and 181 MPa and compared to stress free isothermal ageing. The precipitates responsible for strength were characterized using dark-field transmission electron microscopy (DFTEM). This allows the experimental Determination of radii distributions of the rod-shaped Al2CuMg precipitates and the evaluation regarding their mean precipitate radius. It was found that the mean precipitate radius enables the comparison of the different microstructural conditions of crept and uncrept samples. The mean precipitate radii of the samples experiencing creep are significantly higher than those of undeformed samples. It was shown that the acquired radii distributions are viable to determine averaged particle radii for comparison of the aged samples. A ripening process including pipe diffusion along dislocations describes the data on coarsening very well for the creep samples. Elsevier B. V. 2018 Materials Science & Engineering A 716 78 86 10.1016/j.msea.2018.01.033 2018-02-12 OPUS4-33527 Beitrag zu einem Tagungsband Epishin, A.I.; Link, T.; Nolze, Gert; Fedelich, Bernard; Schriever, Sina Creep behaviour of the single-crystal nickel-base superalloy CMSX-4 at ultra-high homologous temperature Data about the creep behaviour of metals and their alloys at temperatures close to the melting point are very limited. The reason is that most engineering alloys are used at temperatures below 0.6-0.8 of their melting point, so, Investigation of creep at higher temperatures has no practical relevance. For some special applications however it is important, in our case hot isostatic pressing (HIP) of single-crystal turbine blades cast from nickel-base superalloys. In order to remove porosity the blades are HlPed at temperatures between y'-solvus and solidus where superalloy has no strengthening y'-phase and therefore is very soft. For example, the Company Howmet Castings HIPs the superalloy CMSX-4 at the temperature 1288aC, which corresponds to a homologous temperature of about 0.97=1561 K/1612 K (solidus temperature). Therefore knowledge about the creep behaviour of CMSX-4 at this temperature and understanding of the creep mechanisms are necessary to model the kinetics of pore closure during HIP as well as to plan the Parameters of the HIP process. 2015 CREEP 2015 - 13th International conference on creep and fracture of engineering materials and structures 825 CREEP 2015 - 13th International conference on creep and fracture of engineering materials and structures Toulouse, France 31.5.2015 04.06.2015 19 20 2016-02-20 OPUS4-51796 Beitrag zu einem Tagungsband Fedelich, Bernard; Feldmann, Titus; Haftaoglu, Cetin; Nolze, Gert; Schriever, Sina; Epishin, A.; Camin, B.; Lopez-Galilea, I.; Ruttert, B.; Theisen, W. Untersuchung des Kriechverhaltens einer Nickelbasis-Superlegierung bei ultrahohen homologen Temperaturen und Anwendung auf das heiß-isostatische Pressen (HIP) Mit Hilfe des HIP-Verfahrens („Hot Isostatic Pressing") werden Poren in der einkristallinen Nickel-Basis Superlegierung CMSX-4 kontinuierlich geschrumpft und dadurch die nach der Erstarrung und der Wärmebehandlung vorhandene Porosität stark reduziert. In diesem Beitrag werden experimentelle und numerische Untersuchungen zu den Mechanismen der Porenschrumpfung zusammengefasst. Es zeigt sich, dass das Verformungsverhalten während Kriechversuchen bei der HIP-Temperatur durch Versetzungsgleitung auf oktaedrischen Ebenen dominiert wird. Dagegen zeigen Messungen der Porositätsabnahme und Simulationen des Porenschließens, dass die Kinetik der Porenschrumpfung durch das Phänomen der Leerstellendiffusion zwischen Poren und Kleinwinkelkorngrenzen („Low Angle Boundary", LAB) bestimmt wird. Im Gegensatz führt die klassische Kristallviskoplastizität zu einer systematischen Überschätzung dieser Kinetik. Der scheinbare Widerspruch lässt sich auflösen, wenn man bedenkt, dass auf der Skala der Poren Versetzungsquellen nicht gleichmäßig verteilt sind, wie in der konventionellen Kristallplastizität implizit angenommen wird. Stattdessen wird in einem weiterführenden Modell davon ausgegangen, das Kleinwinkelkorngrenzen (LABs) als Versetzungsquellen fungieren, während die Scherspannungen sehr stark in der Nähe der Poren lokalisiert sind, was die Emission von Versetzungen deutlich reduziert. Forschungsvereinigung Warmfeste Stähle und Hochtemperaturwerkstoffe 2020 Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe 2020 978-3-946885-95-5 Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe Online meeting 27.11.2020 27.11.2020 28 39 2020-12-10 OPUS4-45660 Zeitschriftenartikel Epishin, A.; Fedelich, Bernard; Nolze, Gert; Schriever, Sina; Feldmann, Titus; Farzik Ijaz, M.; Viguier, B.; Poquillon, D.; Le Bouar, Y.; Ruffini, A.; Finel, A. Creep of single crystals of nickel-based superalloys at ultra-high homologous temperature The creep behavior of single crystals of the nickel-based superalloy CMSX-4 was investigated at 1288 °C, which is the temperature of the hot isostatic pressing treatment applied to this superalloy in the industry. It was found that at this super-solvus temperature, where no gammaPrime-strengthening occurs, the superalloy is very soft and rapidly deforms under stresses between 4 and 16 MPa. The creep resistance was found to be very anisotropic, e.g., the creep rate of [001] crystals was about 11 times higher than that of a [111] crystal. The specimens of different orientations also showed a very different necking behavior. The reduction of the cross-sectional area psi of [001] crystals reached nearly 100 pct, while for a [111] crystal psi = 62 pct. The EBSD analysis of deformed specimens showed that despite such a large local strain the [001] crystals did not recrystallize, while a less deformed [111] crystal totally recrystallized within the necking zone. The recrystallization degree was found to be correlated with deformation behavior as well as with dwell time at high temperature. From the analysis of the obtained results (creep anisotropy, stress dependence of the creep rate, traces of shear deformation, and TEM observations), it was concluded that the main strain contribution resulted from <01-1>{111} octahedral slip. New York, NY Springer Sciences & Business Media The Minerals, Metals and Materials Society (TMS) 2018 Metallurgical and materials transactions A 49A 3rd European Conference on Superalloys (‘Eurosuperalloys 2018’) Oxford, UK 9.9.2018 13.9.2018 9 3973 3987 10.1007/s11661-018-4729-6 2018-08-07 OPUS4-40750 Beitrag zu einem Tagungsband Rockenhäuser, Christian; Schriever, Sina; Skrotzki, Birgit Panfilov, Peter; Kodzhaspirov, Georgii Microstructural evolution during creep of Al-alloy 2618A The aluminum alloy 2618A is an Al-Cu-Mg alloy with additions of Fe and Ni, which was designed for long-term operation at elevated temperature in transportation and aerospace industries. Typical applications include aircraft parts and structures (sheet material) or engine components such as turbo charger centrifugal compressor wheels (forged material). Such components are subjected to prolonged aging during service, (e.g. 50 000 h) at temperatures which are close to their age hardening temperature (ca. 190 °C). The microstructural evolution during creep exposure is studied. St. Petersburg, Russia SpbPU Publisher 2017 Proceedings Creep 2017 978-5-7422-5799-8 Creep 2017 St. Petersburg, Russia 19.07.2017 21.07.2017 80 81 2017-06-27 OPUS4-58263 Vortrag Kianinejad, kaveh; Fedelich, Bernard; Darvishi Kamachali, Reza; Schriever, Sina; Manzoni, Anna Maria; Agudo Jacome, Leonardo; Megahed, Sandra; Kamrani, Sepideh; Saliwan-Neumann, Romeo Experimentally informed multiscale creep modelling of additive manufactured Ni-based superalloys Excellent creep resistance at elevated temperatures, i.e. T / T_m> 0.5, due to γ-γ' microstructure is one of the main properties of nickel-based superalloys. Due to its great importance for industrial applications, a remarkable amount of research has been devoted to understanding the underlying deformation mechanism in a wide spectrum of temperature and loading conditions. Additive manufactured (AM) nickel-based superalloys while being governed by similar γ-γ' microstructure, exhibit AM-process specific microstructural characteristics, such as columnar grains, strong crystallographic texture (typically <001> fiber texture parallel to build direction) and compositional inhomogeneity, which in turn leads to anisotropic creep response in both stationary and tertiary phases. Despite the deep insights achieved recently on the correlation between process parameters and the resulting microstructure, the anisotropic creep behavior and corresponding deformation mechanism of these materials are insufficiently understood so far. One reason for this is the lack of capable material models that can link the microstructure to the mechanical behavior. To overcome this challenge, a multiscale microstructure-based approach has been applied by coupling crystal plasticity (CP) and polycrystal model which enables the inclusion of different deformation mechanisms and microstructural characteristics such as crystallographic texture and grain morphology. The method has been applied to experimental data for AM-manufactured INCONEL-738LC (IN738). The effect of different slip systems, texture, and morphology on creep anisotropy at 850°C has been investigated. Results suggest a strong correlation between superlattice extrinsic stacking fault (SESF) and microtwinning and observed creep anisotropy. 2023 EUROMAT 23 Frankfurt a. M., Germany 04.09.2023 2023-09-14