Evolution of the deformation texture and yield locus shape in an AZ31 Mg alloy sheet under uniaxial loading

A visco-plastic self-consistent (VPSC) polycrystal model was employed to simulate the evolution of yield locus shape in a polycrystalline AZ31 Mg alloy sheet under uniaxial loading. Macroscopic velocity gradients were imposed to calculate a full yield locus on the two-dimensional projection of a stress potential. The directions of the plastic strain rate vector were evaluated for various loading directions at the four quadrants of yield locus. The change of yield locus shape during plastic deformation was explained by texture evolution and the variation in the relative activity of each deformation mode. The validity of the polycrystal model for simulation of yield locus in a polycrystalline AZ31 Mg alloy sheet was demonstrated through the comparison of simulated deformation texture and R-value, which is a differential property of yield locus, with the experimental results.