Experimental investigation into effect of annealing treatment on springback of magnesium alloy sheets

摘要

The purpose of this work is to experimentally investigate the effect of annealing treatment on thenspringback at room temperature for AZ31 magnesium alloy sheets, which were produced bynrolling in a reversible warm mill after twin roll strip casting. Microstructure evolutions wereninvestigated using optical microscopy after annealing at temperatures ranging from 350 to 450uC.nBoth tension and compression tests were performed at room temperature for the annealingntreated samples to show the influence of annealing treatment on the asymmetric yieldingnbehaviour of AZ31 Mg alloy sheets. In order to evaluate the springback in the stamping process,nthe V shaped air bending tests were performed and the angle changes after springback werenmeasured. The tensile and compressive yield stresses were deteriorated because of thencoarsening of grain size with increasing annealing temperature. The yielding behaviours ofntension and compression show a large asymmetry, as well as the Hall–Petch slope. The Hall–nPetch slope of the compressive yield stress is larger than that of the tensile yield stress. Thenspringback angle in the V shaped air bending tests was decreased with increasing annealingntemperature.