Effect of Bi, Sb, and Ca additions on the hot hardness and microstructure of cast Mg-5Sn alloy

▶ Hot hardness of Mg-5Sn based alloys showed transition points in the range 418-428 K. ▶ Addition of Bi, Sb, and Ca to Mg-5Sn improved the hot hardness of the alloys. ▶ Effectiveness of the alloying elements was characterized by transition temperature and softening coefficient. ▶ The enhanced materials' resistance to high temperature deformation was caused by the thermally stable Mg3Bi2, Mg3Sb2, and CaMgSn intermetallic particles. ▶ The Mg-5Sn-2Ca alloy showed the best hot hardness behavior, due to the finer structure and formation of CaMgSn particles.