Improving the mechanical properties of a ZM61 magnesium alloy by pre rolling and high strain rate rolling

The effects of pre-rolling treatment on the grain refinement, dynamic precipitation and mechanical properties of a Mg-6 wt%Zn-1 wt%Mn alloy (ZM61) processed by high strain rate rolling (HSRR) were investigated. The results indicate that: (1) a large number of twins and microbands formed during pre-rolling treatment, which provide plenty of nucleation sites for dynamic recrystallization (DRX) during subsequent HSRR. As a result, an average grain size of 0.8 mu m and a DRX degree of 99% were obtained for the alloy after pre-rolling and subsequent HSRR; (2) the pre-rolling treatment also resulted in the formation of a high density of fine precipitates, distributing uniformly in the matrix; (3) an excellent balance of the strength and ductility was achieved for the alloy processed by pre-rolling and subsequent HSRR, which is superior to that of the alloy processed only by HSRR.