Simulation of the dendrite growth during directional solidification under steady magnetic field using three-dimensional cellular automaton method coupled with Eulerian multiphase

Abstract

A three-dimensional cellular automaton method coupled with Eulerian multiphase is developed to investigate the dendrite growth during directional solidification under a steady magnetic field. In this model, the heat and solute transports, dendrite growth, thermal and solutal buoyancy, Thermo-Electro-Magnetic force and induced Lorentz force are taken into account. The simulation results reveal that asymmetric characteristics of dendrites are observed during the directional solidification of Al-2.5wt%Cu alloy under a steady magnetic field because of the intense melt flow occurring in the vicinity of the solid-liquid interface. The simulated results show that the numerical boundary condition has significant influence on the formation of tilted interface due to the changing of melt flow. Meanwhile, dendrites with various of preferred orientation are set to investigate the melt flow on the evolution of dendritic morphology during the directional solidification under the steady magnetic field. Finally, a criterion of u→l∇cl in the vicinity of solid-liquid interface is proposed to illustrate the evolution mechanism of dendritic morphology under steady magnetic field, i.e., the region with u→l∇cl>0 promoting the dendrites growth and u→l∇cl<0 suppressing the dendrites growth.