Effect of Ca on the microstructure, texture and mechanical properties in Mg–Zn–Mn based alloy

Abstract

We investigated the role of Ca and hot-rolling condition in the microstructure evolution and mechanical properties in the ZM40 alloy sheets. While the strong basal texture was developed in the as-rolled ZM40 alloy regardless of rolling conditions, the specimen reheating between rolling passes resulted in the weakening of the basal texture in the as-rolled ZMX400 alloy. The solution treatment after the hot-rolling led to the grain coarsening to ~20 μm while keeping the strong basal texture in the ZM40 alloy. The solution treated ZMX400 alloy showed bimodal grain structures consisting of larger grains than those observed in the ZM40 alloy, and the basal texture was further weakened. This resulted in a significant improvement of room temperature formability to the index Erichsen value of 6 mm. In spite of the coarser grain structure and weakened basal texture, the solution treated ZMX400 alloys showed comparable strengths with the ZM40 alloy. This is because higher number density of fine α-Mn phase particles are distributed in the ZMX400 alloy than the ZM40 alloy.