Influence of cooling rate on solidification behavior of sand-cast Mg-10Gd-3Y-0.4Zr alloy
(1. National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of
Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Materials Science and Engineering Department, North Carolina State University, Raleigh, NC 27695-7907, USA)
Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Materials Science and Engineering Department, North Carolina State University, Raleigh, NC 27695-7907, USA)
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 ？TN. 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.
Key words: Mg-10Gd-3Y-0.4Zr; sand-cast; cooling rate; thermal analysis; solidification behavior