Enhanced microstructure homogeneity and mechanical properties of AZ31 magnesium alloy by repetitive upsetting

► As-cast AZ31 Mg alloy is refined by repetitive upsetting at 250-350 °C. ► Fine homogeneous microstructure is achieved after 5 passes at 350 °C. ► Simultaneous increase in both strength and ductility is observed during RU process. ► Grain size is less than 2.6 and 1.3 μm after 5 RU passes at 350 and 250 °C. ► After RU at 350 °C, AZ31 alloy has a 304 MPa tensile strength and 28% elongation.