Slip System Analysis of Magnesium Alloy AZ31B in Warm Compression by Visco-Plastic Self-Consistent Simulation

The active deformation mode (slip systems and twinning) of extruded AZ31B alloy (Mg-3Al-1Zn, mass%) during compression at RT, 100°C and 150°C was investigated by visco-plastic self-consistent (VPSC) simulation. Compression tests were first performed to obtain compression curve of AZ31B. The VPSC model was fitted to the compression curves to estimate the Voce hardening parameters which are required for the VPSC simulation. In the case of compression along the extrusion direction, work-hardening occurred rapidly with the transition of dominant deformation modes at all temperatures. In the case of compression to the other directions, basal 〈a〉 slip was dominant throughout the deformation at all compression temperatures. In addition, prismatic 〈a〉 slip and tensile twin were active in the early stage of deformation, and pyramidal 〈c + a〉 slip became active in the later stage of deformation. Pyramidal 〈c + a〉 slip became more active with increasing temperature from RT to 100°C, whereas basal 〈a〉 and prismatic 〈a〉 slips became more active with increasing temperature from 100°C to 150°C. These different trends in the change of the active slip system with increasing temperature can be attributed to the CRSS maximum of the pyramidal 〈c + a〉 slip located around 100°C.