Microstructure and mechanical properties of ZK60 alloy processed by two-step equal channel angular pressing

A ZK60 alloy was processed by two-step equal channel angular pressing (ECAP) in order to refine the grain size and enhance the mechanical properties. The results show that fine grain size less than 1 μm was obtained after the two-step ECAP process, 4 passes at 513 K, followed by another 4 passes at 453 K. The strength of ZK60 alloy decreased after the single-step ECAP process but recovered after two-step ECAP process. The strength decrease was related to the texture softening. Compared with the single-step ECAP at 513 K, the two-step ECAP has significantly improved the yield strength and ultimate tensile strength of the alloy. The mechanism of the notable grain refinement of the ECAP process was mainly attributed to continuous dynamic recovery and recrystallization.