Deformability enhancement of rare earth magnesium alloy during electroplastic rolling

Abstract

The rare earth magnesium alloys present poor deformability because of fewer slip systems and RE elements addition, which is manifested as edge cracks during hot rolling. Here it was found that applied pulsed current during rolling for Mg-13Gd-4Y-2Zn-0.5Zr rare earth magnesium alloy can effectively inhibit the generation of edge cracks. By comparing the number of macroscopic cracks around the hot and electroplastic rolled samples with the same initial rolling temperature (380 °C) and different reductions (30 %, 35 %, 40 %), the results showed the pure electric effect presents a senior enhancement on deformability of material, because the dislocation density and texture intensity can be decreased during electroplastic rolling. Meanwhile, the number of macroscopic edge cracks of the rolled plate is reduced from 38 of hot rolling (30 % reduction) to 0 of electroplastic rolling (30 % reduction), indicating that the deformability is improved. Besides, the intergranular W phases were basically dissolved, and the block-shaped Long-Period Stacking Ordered (LPSO) phases can be transferred to the lamellar ones. The grain size of the electroplastic rolling samples present finer than that of the hot rolling, because of the accelerated dynamic recrystallization.