Unveiling the microstructure evolution and plastic deformation mechanism of asymmetric forging and extrusion process

Exploring novel thermomechanical processes for large-sized samples is vital for the widespread application of Magnesium (Mg) alloy. In this work, we developed an asymmetric forging and extrusion (AFE) process and successfully optimized the microstructure and mechanical properties of AZ31 alloy. The effect of the AFE process on microstructure and texture evolution was investigated by electron backscatter diffraction (EBSD) and finite element analysis (FEA). The mechanical behavior of AZ31 alloy after the AFE process was analyzed. The results reveal that the elevated equivalent strain enhances the density of dislocations and twins, which triggers twin- induced dynamic recrystallization (TDRX) and accelerates the DRX process. The asymmetric distribution of equivalent strain results in the deflection of the c-axis of DRXed grains and the increase in misorientation of adjacent grains, which is conducive to texture weakening. The comprehensive mechanical properties have been thus improved due to grain refinement and texture weakening. These results provide valuable insights for understanding the asymmetric deformation mechanism and improving high-quality Mg alloys' manufacturing efficiency.