A superior combination of strength-ductility in CoCrFeNiMn high-entropy alloy induced by asymmetric rolling and subsequent annealing treatment

CoCrFeMnNi high-entropy alloy with a smaller average grain size and gradient microstructure was produced by asymmetric rolling (ASR) and subsequent annealing treatment, which gave rise to a superior combination of strength-ductility. High back stress, working hardening and geometrically necessary dislocations were detected in the gradient structure. The ultra-high strength of the CoCrFeMnNi high-entropy alloy was related to the fine grain and high back-stress, while the superior ductility was ascribed to the gradient structure and fine grain. ASR followed by annealing might be a novel strategy for designing high entropy alloys with high performance.