Impact of interstitial C on phase stability and stacking-fault energy of the CrMnFeCoNi high-entropy alloy

Journal article (2019)

Authors

Yuji Ikeda Kyoto University, Max-Planck-Institut für Eisenforschung
Isao Tanaka Kyoto University, Japan Fine Ceramics Center, National Institute for Materials Science
Jörg Neugebauer Max-Planck-Institut für Eisenforschung
F.H.W. Körmann Max-Planck-Institut für Eisenforschung, (OLD) MSE-7
Research Group
(OLD) MSE-7
Copyright: © 2019 Yuji Ikeda, Isao Tanaka, Jörg Neugebauer, F.H.W. Körmann
DOI: https://doi.org/10.1103/PhysRevMaterials.3.113603
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Published Date

2019

Language

English

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Research Group

(OLD) MSE-7

Abstract

Interstitial alloying in CrMnFeCoNi-based high-entropy alloys is known to modify their mechanical properties. Specifically, strength can be increased due to interstitial solid-solution hardening, while simultaneously affecting ductility. In this paper, first-principles calculations are carried out to analyze the impact of interstitial C atoms on CrMnFeCoNi in the fcc and the hcp phases. Our results show that C solution energies are widely spread and sensitively depend on the specific local environments. Using the computed solution-energy distributions together with statistical mechanics concepts, we determine the impact of C on the phase stability. C atoms are found to stabilize the fcc phase as compared to the hcp phase, indicating that the stacking-fault energy of CrMnFeCoNi increases due to C alloying. Using our extensive set of first-principles computed solution energies, correlations between them and local environments around the C atoms are investigated. This analysis reveals, e.g., that the local valence-electron concentration around a C atom is well correlated with its solution energy.