Low cycle fatigue behavior and deformation mechanism of core–shell heterogeneous grain structured CoCrFeMnNi high-entropy alloy

Heterogeneous grain structured high-entropy alloys (HEAs) exhibit excellent strength-ductility synergy due to the peculiar grain structure topology. However, the understanding of cyclic response and deformation mechanism under low cycle fatigue (LCF) loading is still inadequate. Therefore, the LCF behavior and deformation mechanism of CoCrFeMnNi HEAs with a three-dimensional core–shell grain structure were investigated in this paper. The effects of core–shell network structure on cyclic response and fatigue life are revealed. The dislocations activity dominantly appears in the soft core regions prior to the hard shell region. The LCF resistance remains when the strain amplitude is below 0.5%.