A CA-FD MODEL FOR DIRECTIONAL SOLIDIFICATION OF Al-7％Si ALLOY WITH DC CURRENT
The dendrite growth of Al-7％Si alloy under the action of direct electric current is simulated by the Cellular Automaton-Finite Difference (CAFD) method in this paper. The dendrite growth in the simulation<*> is controlled by the CA rules considering the supercooling, the interfacial curvature and crystal anisotropy. The distribution of the DC current density, the temperature profile and the melt convection 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 passes through the interface as the asymmetric distribution of conductance. The thermal gradient near the interface increases and the supercooling is reduced under the action of Joule heat, which delays the growth of the dendrite core and shrinks of the second arms of dendrites synchronously. With the current increases, the dendrite arm spacing decreases and the interface trends to transform from dendrite to cellular. The Lorentz force also causes convection of the melt which strongly affects the dendrite growth as the distribution of composition and the thermal profile near S-L interface is markedly changed by the convection.
Dendrite growth DC electric current Lorentz force Convection
Xiaohui FENG Yuansheng YANG Wenhui TONG
Institute of Metal Research, Chinese Academy of Sciences Shenyang, 110016, China
国际会议
大连
英文
267-274
2007-08-19（万方平台首次上网日期，不代表论文的发表时间）