Simulation of Strain-Softening Behaviors in an AZ31 Mg Alloy Showing Distinct Twin-Induced Reorientation Before a Peak Stress

To investigate strain-softening behavior during plastic deformation of an AZ31 Mg alloy, cylindrical specimens were compressed in a rolling direction at 300 degrees C. Experimental evidence revealed that an inhomogeneous microstructure evolved due to the softening behavior associated with deformation at elevated temperatures. The large grains that reoriented as a result of deformation twinning were free of dynamic recrystallization (DRX). Fine grains nucleated at grain boundaries of grains were deformed by a slip-dominated mechanism, which accommodated the external strain. A visco-plastic self-consistent (VPSC) polycrystal model was used to simulate softening of the flow stress curve and texture evolution during uniaxial compression. A softening scheme was implemented in the polycrystal model to predict the softening phenomenon and texture evolution after the peak stress. The original VPSC model was modified to Simulate texture evolution in an AZ31 Mg alloy that exhibited twin-dominated deformation before the peak stress.