Elevated-temperature cyclic deformation mechanisms of CoCrNi in comparison to CoCrFeMnNi

Lu, K. and Knöpfle, F. and Chauhan, A. and Litvinov, D. and Schneider, M. and Laplanche, G. and Aktaa, J.

Volume: 220 Pages:
DOI: 10.1016/j.scriptamat.2022.114926
Published: 2022

We report the cyclic deformation behavior of CoCrNi at 550 °C under a strain amplitude of ± 0.5% and compare it to that of CoCrFeMnNi. CoCrNi manifests cyclic hardening followed by minor softening and a near-steady state until failure. Transmission electron microscopy investigations of CoCrNi revealed that increasing the number of cycles from 10 to 2500/5000 leads to a transition of dislocation arrangements from slip bands to tangles. Compared to CoCrFeMnNi, CoCrNi exhibits higher strength, longer lifetime and persistent serrated flow. Owing to its lower stacking fault energy (even at 550 °C), planar slip is more pronounced in CoCrNi than CoCrFeMnNi, which additionally shows wavy slip. © 2022 Acta Materialia Inc.

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