Enhanced rollability of Mg-3Al-1Zn alloy by pulsed electric current: a comparative study

摘要

Experiments were designed to compare the rollability of magnesium alloy AZ31 sheet in two rolling schedules at the same rolling temperatures: multi-pass electroplastic rolling (ER) and warm rolling (WR). While cracks occur in WR sheet at an accumulative true strain of -0.24, the sheet can be rolled by ER up to an accumulative true strain of -1.09 without edge-cracking. This rollability enhancement in ER sheet was found to be related to the improved homogeneity of plastic deformation and dynamic recrystallization (DRX), which postpones the crack initiation. A 'twinning - shear banding - DRX' microstructure evolution model was proposed to explain the effect of pulsed electric current on the homogeneity of deformation and subsequent DRX. The use of ER sheet could pave the way for low-cost applications of lightweight magnesium components. (C) 2016 Elsevier Ltd. All rights reserved.