Achieving bimodal microstructure and enhanced tensile properties of Mg-6Sn-3Al-1Zn alloy by tailoring deformation amount during pack rolling

The Mg-6Sn-3Al-1Zn alloys were pack-rolled with various amounts of deformation at 400°C. The results indicated that a bimodal microstructure formed after pack-rolling. With the increase in the amounts of deformation, the average grain size of the small grains increased first and then decreased, while the average grain size of the big grains decreased. Both the volume fraction of twins and the average grain size of the alloy decreased with the increasing amounts of deformation, resulting in the improvement of the tensile properties of the alloy. When the amount of deformation was 65%, the mechanical properties of the alloys were optimal; the tensile strength, yield strength, and elongation-to-failure were 288 MPa, 188 MPa, and 15.7%, respectively.