Hot tearing susceptibility of Mg-xZn-2Y alloys

Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg-2%Y alloy were studied in a constrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate that the hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS of Mg-xZn-2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Zn addition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop during solidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS of Mg-xZn-2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements.