Role of Texture in Electropulsing Anisotropy of AZ31 Mg Alloy Rolled Sheet

Abstract

Despite increased interest in electropulsing treatment (EPT), several of its fundamental principles remain unclear. This study investigated the profound effect of crystallographic texture on EPT-induced microstructural evolution. A hot-rolled AZ31 Mg alloy sheet was designed to have twin-free equiaxed grains, thereby isolating the texture as the sole variable. The results revealed significant electropulsing anisotropy in the alloy. EPT along the rolling direction (RD) remarkably accelerated grain growth and recovery, whereas EPT along the normal direction (ND) suppressed these changes, even under identical current densities. This anisotropy was clarified by separately investigating the thermal and athermal effects. Shifting the electropulsing direction from ND to RD increased the electrical resistivity of the material, producing a more pronounced thermal response (i.e., Joule heating). Furthermore, this directional shift increased the athermal contribution of EPT. It offset a significant current density difference of up to 6 A·mm^− 2 while maintaining similar microstructural evolution. Thus, both the thermal and athermal contributions of the EPT were anisotropic, consistently changing in the order RD > diagonal direction > ND. This study provides critical insights into the interplay between the texture and EPT mechanisms, which is crucial for optimizing the process and developing advanced metallic materials with precisely tailored microstructures.