Atomistic tensile deformation mechanisms in a CrCoNi medium-entropy alloy with gradient nano-grained structure at cryogenic temperature

Large-scale molecular dynamics (MD) simulations have been utilized to reveal the atomistic deformation mechanisms of a CrCoNi medium-entropy alloy (MEA) with gradient nano-grained (GNG) structure in present study. Strong strain hardening was observed at elasto-plastic transition stage, which could be attributed Masing hardening. After yielding, obvious partitioning tensile detected structure, indicates existence hetero-deformation induced (HDI) effect and account for higher flow stress than that calculated by rule mixture from its homogenous (NG) structured counterparts. Moreover, stacking fault factor (corresponding strain), demonstrates intensity dislocation behaviors, also structure. The differences factors each grain size area were found smaller those homogeneous counterparts, influence forward back on motion near zone boundary between hard grains soft larger grains, further verifying presence