Phase-field simulation of dendrite growth of Magnesium alloy under non-isothermal solidification

摘要

The phase-field model was built by coupling with the concentration field and temperature field, The dendrite growth process of Magnesium alloy was simulated under the different anisotropic strength and different undercooling. The results show that with the enlarge of anisotropic strength, dendritic morphology change from seaweed-like to snow-like, trunk grows along the optimal direction, and the secondary dendrite arm grow along the most optimize direction as well; With undercooling increasing, the more coarse primary dendrite arm, the more developed secondary dendrite arm, dendrites around the thermal diffusion layer becomes thinner, and dendrite tip's thermal diffusion layer is thinner than the dendrite roots, but segregation phenomenon decreases slowly. When △=1.0, the grain will directly generate cellular dendrite and it does't appear segregation phenomenon.