Effect of temperature of differential speed rolling on room temperature mechanical properties and texture in an AZ31 magnesium alloy

Differential speed rolling (DSR) was applied to the AZ31 magnesium alloy, intended to modify the texture and thus to enhance the room temperature ductility. Especially, effect of DSR temperature on resulting room temperature tensile properties and texture was investigated at a fixed rolling speed ratio of 1.1. The strength was not affected by the rolling temperature: the yield strength and the ultimate tensile strength for all materials processed by DSR were approximately 240 and 290 MPa, respectively. On the other hand, elongation-to-failure increased from 13.6 to 18.5% with decreasing rolling temperature from 573 to 473 K. In addition, the material processed by DSR exhibited approximately 1.5 times larger ductility than that by conventional symmetric rolling at a rolling temperature of 473 K. The DSR at 523 and 473 K resulted in the basal plane orientation at the position inclined by ∼5 and 8° from the normal direction toward the rolling direction, respectively. It was suggested that the higher ductility of the material processed at lower temperatures is attributed to the slight change in the basal plane orientation and/or reduction in grain size.