The effect of double extrusion on the microstructure and mechanical properties of Mg-Zn-Ca alloy

The Mg-4.50Zn-1.13Ca (wt%) alloy was subjected to double extrusion, and the microstructure and mechanical properties of the extruded alloys were investigated. Double extrusion refined the microstructure significantly, resulting in the enhancement of mechanical properties of the double-extruded alloys compared with the single-extruded alloy. The yield strength of the single-extruded alloy was 173MPa, while the value was increased to 320MPa and 370MPa after subsequent second extrusion at 300°C and 250°C, respectively. The second extrusion ratio had little effect on the microstructure and mechanical properties of the double-extruded alloys, while grain size was decreased and strength was increased with the decrease of double extrusion temperature. The double-extruded Mg-Zn-Ca alloy exhibited superior elevated temperature mechanical properties, which was attributed to the fine stable Ca₂Mg₆Zn₃ intermetallic compound particles dispersed in the alloy.