Effects of interstitial C and N on hydrogen embrittlement behavior of non-equiatomic metastable FeMnCoCr high-entropy alloys

• DOI: 10.1016/j.corsci.2021.109933
• Publication Date: 2021-11-06T15:27:17Z
• Authors: Zhenghong Fu; Pengfei Wu; Shuya Zhu; Kefu Gan; Dingshun Yan; Zhiming Li
• Keywords: Stacking-fault energy; Embrittlement

Abstract The hydrogen embrittlement behavior of C-doped and C-N co-doped non-equiatomic FeMnCoCr high-entropy alloys were investigated by slow strain rate tensile tests (1 × 10−5 s−1) under in-situ electrochemical hydrogen charging. Multi-scale microstructural analysis suggests that appropriate phase stability and stacking fault energy adjusted by C-doping provide the alloy with slightly greater resistance to hydrogen embrittlement with the formation of abundant deformation-induced twins and e-martensite during deformation. The C-N free alloy shows grain boundary and e/γ interface cracking even though the γ and e phases have high deformability. C-N co-doping promotes planar dislocation slip, assisting grain- and twin-boundary cracking under deformation in hydrogen.