Optimized Hot Tearing Resistance of VW63K Magnesium Alloy

Mg-6Gd-3Y-0.5Zr (VW63K) alloy is widely used in the aerospace field because of its excellent mechanical properties not only at room temperature but also under high service temperature. In this study, the effect of minor changes to the Y alloying levels on the hot tearing behavior of VW63K alloys was researched by using a "T" mold, with pouring temperature of 720 °C and mold temperature of 150 °C. The results show that the hot tearing susceptibility of the alloy decreases gradually with the increase of Y content from 2.8 to 3.4 wt%. The reason for this phenomenon is that high content of Y element narrows the susceptible freezing range and increases the eutectic liquid fraction of the alloy, which is helpful for the alloy to have a better compensation at the late stage of solidification and, thereby decreasing the hot tearing susceptibility.