Fatigue behavior of CoCrFeMnNi high-entropy alloy under fully reversed cyclic deformation

Abstract Bulk ultrafine-grained (UFG) CoCrFeMnNi high-entropy alloy (HEA) with fully recrystallized microstructure was processed by cold rolling and annealing treatment. The high-cycle fatigue behaviors of the UFG HEA and a coarse-grained (CG) counterpart were investigated under fully reversed cyclic deformation. The fatigue strength of the UFG HEA can be significantly enhanced by refining the grain size. However, no grain coarsening was observed in the UFG HEA during fatigue tests. Mechanisms for the superior mechanical properties of the UFG HEA were explored.