Effect of Mn addition on microstructure, texture and mechanical properties of Mg–Zn–Ca alloy

The effect of trace Mn addition on the microstructure, texture and mechanical properties of the as-cast and as-extruded Mg–5.25 wt.% Zn–0.6 wt.% Ca (ZX51) alloys was investigated in this study. Mn addition had a negligible effect on the grain size of the as-cast ZX51 alloy. However, the addition of Mn led to the obvious decrease of grain size in the as-extruded Mg–5.25 wt.% Zn–0.6 wt.% Ca–0.3 wt.% Mn (ZXM510) alloy, because the Mn addition restricted the grain growth during the hot extrusion process. After the addition of Mn, the basal fiber texture with most of {0 0 0 2} planes parallel to the extrusion direction (ED) was significantly enhanced in the as-extruded ZXM510 alloy. Both tensile yield strength (TYS) and ultimate tensile strength (UTS) were increased in the as-extruded ZXM510 alloy, while the ductility was slightly decreased, which was ascribed to the grain refinement and texture strengthening.

Research highlights
► The grain size of the as-extruded Mg–Zn–Ca alloy was refined by trace Mn addition.
► The basal texture was enhanced in the as-extruded Mg–Zn–Ca–Mn alloy due to the lower volume fraction of recrystallized grains.
► The tensile yield strength (TYS) of Mg–Zn–Ca alloy was improved through trace Mn addition, a good balance of strength and ductility was achieved.