Phase field simulation of Al-Si binary dendritic growth and micro-segregation patterns under convection

Phase field method was used to simulate the single dendrite and multi-dendrite growth of Al-2 mol%Si under convection. The influence of flow on the dendrite morphology and the concentration was studied during the alloy solidification, and the micro-segregation was investigated by changing the forced flow velocity. The results show that upstream dendritic arm is promoted with convection, while the downstream is inhibited, and the perpendicular arms grow towards to upstream direction. As flow velocity increases, the upstream dendritic arm grows fast, and the concentration increases, but the downstream arm is opposite. It is helpful to improve micro-segregation by increasing convection velocity. Compared to single dendrite, the multi-dendrite growth is complicated due to the interaction of the dendrites.