Effect of Y content on hot tearing susceptibility and mechanical properties of AXJ530-xY alloys

The effect of the addition amount of Y on the hot tearing susceptibility of AXJ530-xY (x = 0, 0.5, 1.0, 2.0 wt%) alloys was studied using a 'T-shaped' hot tearing mold with solidification shrinkage force acquisition system and solidification temperature acquisition system. The mechanical properties of the alloys were measured by tensile test. The microstructure of the AXJ530-xY alloys was analyzed by XRD, SEM and EDS. The experimental results show that Al2Y phase is preferentially formed by the combination of Y and Al elements, which reduces the amount of the alpha-Mg + (Mg, Al)(2)Ca eutectic phase. Therefore, the residual liquid phase which can participate in the feeding after the solidification of the alloy reduced, resulting in the increment the hot tearing susceptibility of the alloys. Among them, the AXJ530-0.5Y alloy has the highest hot tearing susceptibility. As the amount of Y continues to increase, the dendrites appear to be remarkably refined and the dendrite coherence temperature is lowered, so that the hot tearing susceptibility of the alloys slightly decreased. However, as the amount of Y added increases, the mechanical properties of the alloy are significantly improved by fine grain strengthening and second phase strengthening.