Meso-modelling study of the mechanical response and texture evolution of magnesium alloy during hot compression

Abstract

The mechanical response and texture evolution of magnesium alloy during hot deformation are closely related to the heterogeneous meso-deformation. The improved Voce hardening law was developed and introduced into the crystal plasticity (CP) theory, and a reconstruction method of textured representative polycrystal was proposed. Three-dimensional crystal plasticity finite element model (3D-CPFEM) was established to meso-simulate the hot compression deformation of ZK61 Mg alloy. The influence of the temperature and strain rate on mechanical response was investigated, and the corresponding texture evolution and the texture transformation mechanism was revealed through meso-simulation. The results show that the 3D-CPFEM with the improved Voce hardening law and the initial texture characteristic can well predict the mechanical response and texture evolution under different temperatures and strain rates during hot compression of ZK61 Mg alloy. The basal plane texture of the ZK61 tubular blank is transformed into the basal fiber texture after hot compression, where the basal plane of grains is deflected gradually from the radial-axial plane to the radial-tangential plane. The texture transformation is attributed to two reasons, i.e., the orientation deflection of the grains with larger basal slip systems Schmid factor (SF) and the orientation retention of the grains whose c-axis tends to be parallel to the axial direction (AD) of the tubular blank. The change of the grain orientation corresponding to the basal plane texture component of the tubular blank has little contribution to the formed basal fiber texture.