Modeling the 3D Plastic Anisotropy of a Magnesium Alloy Processed Using Severe Plastic Deformation

Abstract

The mechanical response of magnesium AZ31 processed using severe plastic deformation is characterized using a two-surface, pressure-insensitive plasticity model. The model captures the 3D plastic anisotropy and the tension–compression asymmetry as the behavior evolves during straining. The model may be viewed as a reduced-order quasi-crystal plasticity model, whereby the two activation surfaces represent glide- and twinning-dominated flow. The two-surface formulation enables independent, yet coupled, hardening laws in terms of effective plastic strains accumulated on either generic deformation system. Material identification was completed using tension and compression specimens oriented along the principal directions of the processed material, E, L, and F, as well as off-axes specimens that bisected the principal planes E–F, L–F, and L–E. Using the nominal stress–strain and lateral strain data from the experiments, this model can capture the anisotropic behavior of this material.