过冷熔体中的树枝晶分枝机制模拟

采用胞元自动机方法,在综合考虑了成分过冷、曲率过冷和界面能各向异性后,通过在界面上施加不同振幅和波长的扰动,对枝晶的分枝机制进行了模拟计算.模拟结果表明,在不同过冷度下,枝晶的分枝程度均会随扰动波长的变化出现一个峰值,而峰值所对应的波长则随过冷度的增大而减小,扰动振幅的变化不影响峰值波长.这一定性结果与界面稳定性理论的分析取得很好的一致.

Numerical Simulation on Dendrite Branching in Undercooled Melt

Under the consideration of concentration undercooling, curvature undercooling and the anisotrophy of interfacial energy, Cellular Automaton method was applied to simulate the dendrite branching mechanism by imposing perturbation with different amplitude and wavelength. The results indicated that the degree of sidebranch increased to peak value and then decreased with the increase of wavelength while the corresponding wavelength at the peak decreased with the increase of undercooling, which was qualitatively agree well with marginal stability theory.