Microstructure and properties of AZ91D alloy with Ca additions

摘要

Ca additions from 0.1 to 1.0 wt. percent to AZ91D alloy produced some grain refinement and thinning of beta-Mg_(17)Al_(12) phase. Increasing the Ca content resulted in the formation of Al_2Ca phase as well as in the reduction in quantity of beta-Mg_(17)Al_(12) phase. The hot tearing susceptibility of the alloy substantially increased with Ca content rise. The ultimate tensile strength and relative elongation worsened that was explained by the presence of Al_2Ca phase on the grain boundaries. The improvement in the yield strength was connected with the grain refinement of the alloy induced by the restriction of the grain growth due to Ca aggregations on the boundaries.