About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling
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Presentation Title |
Deformation Mechanisms of CoCrNi and CoCrFeMnNi MPEAs under Low-cycle Fatigue Loading: Comparison and Correlation with Lifetime |
Author(s) |
Kaiju Lu, Ankur Chauhan, Aditya Srinivasan Tirunilai, Alexander Kauffmann, Martin Heilmaier, Mike Schneider, Guillaume Laplanche, Jens Freudenberger, Jarir Aktaa |
On-Site Speaker (Planned) |
Jarir Aktaa |
Abstract Scope |
Equiatomic CoCrNi and CoCrFeMnNi FCC MPEAs have attracted tremendous attention due to their excellent strength-ductility combinations. However, their low-cycle fatigue (LCF) behaviors are not fully clear yet. In this talk, the LCF behaviors of CoCrNi and CoCrFeMnNi at RT under different strain amplitudes will be given and correlated to their microstructural evolution.
Both alloys manifest cyclic hardening followed by softening and a near steady state until failure. CoCrNi exhibits higher strength and longer lifetime than CoCrFeMnNi. TEM characterizations reveal their unique dislocation patterns, including slip bands, high-density dislcoation walls (HDDWs), extended stacking faults, PSB-walls and/or cells for CoCrNi; slip bands, PSB-walls, labyrinth and/or cells for CoCrFeMnNi, which also vary with strain amplitudes. The difference in their deformation mechanisms (including the nature of dislocations involved) is rooted by their distinct SFEs and can explain CoCrNi’s superior lifetime. Furthermore, the reasons for their cyclic stress responses will also be addressed. |
Proceedings Inclusion? |
Planned: |
Keywords |
High-Entropy Alloys, Mechanical Properties, Characterization |