Effects of Texture and Triaxiality on the Plasticity of Magnesium Alloys

Abstract

Understanding the role of triaxiality is key in the damage evolution of engineering alloys. In low symmetry materials, e.g. magnesium, the role of triaxiality in damage evolution is complicated by the presence of protean deformation mechanisms, which exhibit high crystallographic plastic anisotropy. We present the results of detailed finite element study of smooth and notched round bar polycrystalline specimens of magnesium, subjected to quasi-static tensile loading. Initial simulated textures mimicking and deviating from typical rolled Mg sheet textures are adopted. Using three-dimensional HCP single crystal plasticity, the effect of these textural variations is highlighted. The role of out-of-plane textural variation is compared to the in-plane variation, and the analysis indicates that out-of-plane deviations in $[10\bar{1}0]$ result in subtle changes to the macroscopic deformation anisotropy and the underlying microscopic deformation slip and twin activity. The role of these textures in the activation of twinning mechanisms is discussed. These results, in conjunction with our recent works, help develop a systematic understanding of the texture-triaxiality-anisotropy interaction in magnesium alloys.