Simulation for Directional Solidification of Al-Si alloy with DC Current
(0) A Cellular Automaton-Finite Difference (CAFD) model is built to simulate the directional solidification of Al-7％Si alloy with direct electric current. The dendrite growth in the model is controlled by the CA rules considering the supercooling, the interfacial curvature and crystal anisotropy. The fields of DC current density, the temperature, the concentration and the electro-magnetic flow caused by the Lorenz force are solved by FD calculation. The simulation results show that the nonplanar S-L interface is changed markedly when the DC current pass through the interface as the asymmetric distribution of electric conductivity. The thermal gradient near the interface increases and the supercooling is reduced by the Joule heat, which delays the dendrite growth. With the current increases, the dendrite arm spacing decreases and the interface trends to transform from dendrite to cellular. The electromigration can notablely change the solute movement, and the Lorentz force causes electro-magnetic flow of the melt. The distribution of composition and the thermal profile near S-L interface is then markedly changed, as a result, the dendrite growth is strongly affected.
Xiao-hui Feng Yuan-sheng Yang
Institute of Metal Research,Chinese Academy of Sciences,China
国际会议
上海
英文
2008-10-13（万方平台首次上网日期，不代表论文的发表时间）