二元合金高速定向凝固过程的相场法数值模拟

利用相场法对二元合金高速定向凝固过程进行了模拟，为简化计算，采用了温度冻结近似.模拟了定向凝固时平界面失稳、界面形态演化、溶质浓度分布以及高速绝对稳定性条件下胞晶向平面晶的转变等，得到了不同抽拉速度下胞晶间距、胞晶尖端温度以及有效溶质分配系数等参数，显示了高速生长条件下的溶质截留效应. 关键词： 定向凝固 相场法 高速绝对稳定性 溶质截留

Phase field modeling of directional solidification of a binary alloy at high velocities

Some computational results on directional solidification of a binary alloy obtained by using the phase field model are reported. Frozen temperature approximatio n is adopted to simplify the modeling. The onset of morphological instability, t he pattern evolution and the solute redistribution are shown. The cell to planar interface transition is modeled near the high velocity absolute stability condi tion. The cell spacings, tip temperatures and solute partitioning coefficients a t different velocities are calculated. The solute trapping is also observed.