Multi-pass large strain rolling of as-cast AZ31 magnesium alloy

Abstract

As-cast AZ31 magnesium alloy subjected to multi-pass large strain rolling was investigated. A successive rolling process up to three passes was carried out at 370°C with a pass reduction of 30%. Deformation microstructure characteristics prove that the dynamic recrystallisation (DRX) mode changed with the increase of rolling passes. In the first pass, DRX related to twinning played a dominant role. But in the third pass, DRX grains mainly appeared around the pre-existing grain boundaries. The ultimate strength and elongation of rolled sheets after three passes rolling are enhanced by 37 and 39%, respectively, compared to the as-cast alloy. Meanwhile, the tensile fracture mode was ductile fracture which was different from the ductile–brittle fracture of as-cast.

The Edge Crack, Texture Evolution, and Mechanical Properties of Mg-1Al-1Sn-Mn Alloy Sheets Prepared Using On-Line Heating Rolling

“…In other words, their c-axes were almost perpendicular to the extrusion or rolling direction. Rolling processes resulted in extremely high amounts of red grains, which is because new grains would rotate, and the c-axis would align parallel to the compression axis as strain increased [32]. It can also be noticed that there is only a small amount of DRX grains around parent grains in Figure 9d.…”