Microstructure and mechanical properties of Mg-4Zn-0.5Ca alloy fabricated by the combination of forging, homogenization and extrusion process

Abstract

The Mg-4Zn-0.5Ca alloy was processed by the combination of forging, homogenization and extrusion in present study. The results showed that homogenization treatment between forging and extrusion process can release stored energy and diminish precipitated MgZn2 phase, both of which result in the finer size and low volume fraction of dynamic recrystallized (DRXed) grains, as well as strong basal plane texture in the as-extruded alloy (FD-H-ED). As compared with the as-extruded alloy without homogenization treatment (FD-ED), the FD-H-ED alloy exhibited high yield strength which is thought to originate from the dislocation strengthening and texture strengthening. Only stage III and stage IV appeared in the θ vs. (σ−σ0.2) curves of FD-ED and FD-H-ED alloys. Large amount of fine DRXed grains in FD-ED alloy led to the high dynamic recovery rate at stage III. However, the unDRXed regions in FD-H-ED alloy resulted in its unobvious starting point and promote the decrease of θ value at Stage Ⅳ.