Microstructure Evolution Simulation of Al-Cu-Mg-Ag alloy in Solidification Process Based on Phase Field Method

Abstract Al-Cu-Mg-Ag alloys are widely used in aerospace field due to their excellent heat resistance, high specific strength and good machinability. In order to obtain excellent performance, the control of its solidification structure is very important, so it is necessary to numerically simulate its solidification structure and then control its structure. In this paper, the solidification phase field model was established by phase field method to study the microstructure evolution during solidification. The solidification process of Al-Cu-Mg-Ag-Si alloy is simulated and verified by experiments. The results show that the grains grow in cellshape and the second phase forms at the grain boundary of α phase. The faster the cooling rate, the smaller the grain size and the lower the content of the second phase. The samples were observed by metallography and scanning electron microscopy, and the phase composition of the as-cast samples was characterized by EDS and XRD. It is verified that the second phase in simulation and experiment is mainly θ phase, and the grain morphology accors with th simulation results.