Abnormal texture development in magnesium alloy Mg-3Al-1Zn during large strain electroplastic rolling: Effect of pulsed electric current

Single pass large strain electroplastic rolling (LSER) was conducted on AZ31 alloy, using pulsed electric current of different current densities, to improve the rollability of magnesium alloy sheet. It was found that TD (transverse direction)-split texture developed in the alloy once the current density exceeded a critical value (in the present case 90 A/mm(2)). Microstructure and texture analysis reveal that deformed grains, rather than the dynamically recrystallized grains, are the major contributor to the overall TD-split texture. Intragranular misorientation axis (IGMA) and viscoplastic self-consistent (VPSC) modeling were employed to analyze the influence of the pulsed electric current on the deformation mechanisms. Prismatic < a > type geometrically necessary dislocations (GNDs) were found to be dominant in the deformed grains of the specimens with TD-split texture. VPSC modeling indicates that the TD-split texture is likely due to the enhanced prismatic < a > activity caused by the electric current. The special athermal effect of the pulsed electric current on the deformation mechanisms makes LSER a promising technique for texture modification in magnesium alloys for improved formability. (C) 2016 Elsevier Ltd. All rights reserved.