Effect of Equal Channel Angular Bending on Microstructure and Properties of AZ31 Magnesium Alloy Sheet

Abstract:

The equal channel angular bending (ECAB) of AZ31 magnesium alloy rolled sheet (2 mm) under different paths was conducted at 150 ℃. The evolutions of microstructure and mechanical properties of the sheet were investigated after 5-pass ECAB along the same path, normal direction rotation path and rolling direction (RD) rotation path. The results show that after 5-pass ECAB, a large amount of extension twinning (ETW) and a certain amount of contraction twinning (CTW) and double twinning (DTW) are introduced into the sheet, which can effectively improve the basal texture of the base plane. After annealing treatment, the elongation of the sheets undergone ECAB is obviously improved. In particular, the area fraction of ETW in the deformed sheet rotated 5 passes around the rolling direction (RD) can reach 28.74%, and after annealing, the elongation can reach 28.8% with a tensile strength of 235.7 MPa. Compared with the original sheet, the relative increase ratio of the elongation is 57.4%, while the tensile strength is only 3.8% lower.