Semi-solid Tensile Behavior and its Relationship with Hot Tearing Susceptibility of Mg-xCa Alloys

To figure out the relationship between semi-solid deformation and hot tearing susceptibility of magnesium alloys, the solid and semi-solid tensile experiments of binary Mg-xCa (x = 0.2, 0.5, and 2 wt%) alloys were conducted by a Gleeble 3500 thermal simulator. The linear contraction of the alloys was measured by a newly developed apparatus based on a constrained rod casting (CRC) hot tearing apparatus. The results indicated that the ultimate tensile strength (UTS) and fracture elongation (FE) of the alloys decreased with the decrease in solid fraction (increase in the test temperature). It is revealed that Mg-0.5Ca alloy exhibited the highest hot tearing susceptibility due to its extremely low ductility even at a high solid fraction of 0.96 and the highest linear contraction among the three alloys.