Effects of Ca addition on as-cast microstructure and mechanical properties of Mg-3Ce-1.2Mn-1Zn (wt.%) magnesium alloy

The effects of Ca addition on the as-cast microstructure and mechanical properties of the Mg-3Ce-1.2Mn-1Zn (wt.%) alloy were investigated by using optical and electron microscopes, differential scanning calorimetry (DSC) analysis, and tensile and creep tests. The results indicate that the additions of 0.3-0.9 wt.%Ca to the Mg-3Ce-1.2Mn-1Zn alloy do not cause an obvious change in the morphology and distribution for the Mg12Ce phase in the alloy. However, the grains and secondary dendrite arm spacings of the Ca-containing alloys are refined, and an increase in Ca amount from 0.3 wt.% to 0.9 wt.% causes the grain size and secondary dendrite arm spacings to gradually decrease, respectively. In addition, the additions of 0.3-0.9 wt.%Ca to the Mg-3Ce-1.2Mn-1Zn alloy can effectively improve the as-cast tensile and creep properties of the alloy, and an increase in Ca amount from 0.3 wt.% to 0.9 wt.% causes the as-cast tensile and creep properties to gradually increase, respectively.