Comparison of the effects of isothermal equal channel angular pressing and multi-directional forging on mechanical properties of AM60 magnesium alloy

This study investigates the correlation between the microstructure and the mechanical strength of AM60 magnesium alloy processed by equal channel angular pressing (ECAP) and multi-directional forging (MDF) at a constant temperature of 220 degrees C. The maximum number of passes was six for both severe plastic deformation (SPD) techniques. The minimum achievable grain size was similar to 1.9 mu m for ECAP while it was only similar to 2.7 mu m for MDF. Despite the monotonous reduction of the grain size, the yield and the ultimate tensile strength values decreased for high equivalent strains which was attributed to the decrease of the dislocation density. The maximum achievable strength was higher for ECAP than that for MDF mainly due to the higher dislocation density. Both ECAP and MDF processing led to an improvement of ductility. Based on the strength results, it is evident that the ECAP process is more effective in improving the mechanical properties of AM60 alloy at 220 degrees C, compared to the MDF process.