界面动力学对过冷熔体中球晶生长界面形态的影响*

摘要

考虑了在非平衡凝固条件下球晶生长过程中界面动力学系数随界面温度的变化,利用渐近分析方法求出了在过冷熔体中球晶生长温度场和界面的近似解析解,研究了非线性界面动力学过冷对于过冷熔体中球晶界面形态和生长速度的影响.研究表明,界面动力学系数越大,球晶的生长速度越快;反之,表明界面动力学系数越小,球晶的生长速度越慢.与忽略界面动力学的情形比较,在球晶生长过程中依赖于界面温度变化的界面动力学显著地减缓了晶体生长的速度.%The change of the interface kinetic coefficient with the interface temperature under the non-equilibrium solidification condition is considered in the growth model of a spherical crystal. The first-order approximation solutions of temperature and interface for the spherical crystal growth in the undercooled melt are obtained by the asymptotic analysis method. The effects of the nonlinear interface kinetic undercooling on the interface morphology and the growth velocity of the spherical crystal in the undercooled melt are studied. The results show that as the interface kinetic coefficient increases, the growth velocity of the spherical crystal increases; as the interface kinetic coefficient decreases, the growth velocity of the spherical crystal decreases. Compared with the situation of neglecting interface kinetics, the nonlinear interface kinetics during crystal growth significantly decreases the growth velocity of the spherical crystal.