Influence of cooling rate on solidification behavior of sand-cast Mg–10Gd–3Y–0.4Zr alloy

Abstract The effect of the cooling rate ranging from 1.4 °C/s to 3.5 °C/s on the solidification behavior of the sand-cast Mg–10Gd–3Y–0.4Zr alloy was studied by computer aided cooling curve analysis (CA-CCA). With the increase in cooling rate, the nucleation temperature (Tα,N) increases from 634.8 °C to 636.3 °C, the minimum temperature (Tα,Min) decreases from 631.9 °C to 630.7 °C, the nucleation undercooling (ΔTN) increases from 2.9 °C to 5.6 °C, the beginning temperature of the eutectic reaction (Teut,N) increases, the time of the eutectic reaction shortens, solidus temperature decreases from 546.0 °C to 541.4 °C, and solidification temperature range (ΔTS) increases by 6.1 °C. The increased nucleation rate () is supposed to be the main reason for the increased ΔTN. Increased value (Teut,N–Teut,G) and shortened time of the eutectic reaction cause the change in the volume fraction and morphology of the second phase.