Effects of crystal orientation and strain rate on strain hardening behavior and mechanical property in TRC-ZA21 magnesium alloy

The mechanical property of magnesium alloys was strongly related to strain hardening behavior, and the mechanical response was influenced by crystal orientation and strain rate. In the present study, uniaxial tensile deformation behaviors with various loading directions and strain rates were conducted in as-annealed TRC-ZA21 alloy with spread distribution of grain orientation. Moreover, the influences of crystal orientation and strain rate on strain hardening behavior and mechanical property was investigated by analyses of corresponding microstructure evolution and deformation mechanism. The results showed that evidently different grain orientation relevance and strain rate dependence of mechanical properties existed. The variation in strain hardening behavior was mainly controlled by dislocation slipping, which resulted in differences in yield elongation, negative instantaneous strain hardening rate and peak strain hardening rate. The strain hardening capability along TD was enhanced by activation of tension twinning, due to the change of grain orientation. The ductility can be elevated by modified connectivity of grain boundary for propagation of basal slip. These findings highlight the influences of grain orientation and strain rate on mechanical properties of Mg alloys, which provide general guidance for developing high-performance Mg alloys.