论文部分内容阅读
对定向凝固界面前沿非稳态溶质扩散场进行了系统的对比分析 ,发现无论在纯扩散还是存在对流的情况下 ,界面前沿的溶质扩散场通常满足指数分布的形式 ,可以采用一个统一的公式来描述界面前沿的瞬态溶质扩散场 .进而在此基础上 ,对定向凝固界面形态稳定性进行了统一的时间相关的非稳态分析 ,发现界面临界稳定性条件的数学描述形式与Mullins和Sekerka理论给出的稳态解完全一致 ,只是用时间相关的浓度梯度GtC 、界面速度Vi、溶质扩散长度l代替了稳态生长中所得到的GC,V ,DL V
The unsteady solute diffusion front of directional solidification interface was systematically contrasted and analyzed. It was found that the solute diffusion front of the interface usually satisfies the exponential distribution in pure diffusion or convection, and a uniform formula can be used The transient solute diffusion field at the front of the interface is described.Furthermore, a unified time-dependent unsteady analysis of the morphological stability of the directional solidification interface is carried out, and the mathematical description of the interface critical stability condition is found to be consistent with the Mullins and Sekerka theory The steady-state solutions given are completely consistent except that the time-dependent concentration gradient GtC, the interface velocity Vi, and the solute diffusion length l are used instead of the GC, V, DL V