Effect of strain rate on the shift of neutral layer in AZ31B alloys during V-bending at warm conditions

The effects of strain rate on the shift of neutral layer in AZ31B magnesium alloy sheets were investigated by V-bending tests with a strain rate of 10-2 s-1, 10-3 s-1, 10-4 s-1 at 423 K. Besides, tension and compression tests on AZ31 Mg sheets along the rolling direction (RD) were also conducted at various strain rates. The results show that the neutral layer of Mg alloys shifts to the outer tensile region during bending and the shifting offset decreases with the strain rate decreasing. The above result is a direct consequence of the observed weakening of the tension-compression asymmetry of the Mg alloy at decreasing strain rate.