界面动力学参数对深胞晶界面形态整体波动不稳定性的影响

Influence of interface kinetics parameters on the overall fluctuation instability of the interface morphology of deep cell crystal

研究界面动力学对定向凝固中深胞晶形态稳定性的影响.应用多重变量法和匹配渐近法,通过寻找系统的模式解,导出了胞晶界面扰动振幅的变化率满足的色散关系,得到了界面形态的量子化条件.结果表明,考虑了界面动力学参数的深胞晶生长的定向凝固系统有两种整体不稳定性机制,整体振荡不稳定机制和低频不稳定性.稳定性分析表明,界面稳定性参数ε与胞晶相对参数λ_(0)有关,低阶时界面动力学参数M_(*)越大,中性模式产生强振荡的枝晶结构的整体波动不稳定性的稳定区域越大.

The effect of interface kinetics on the stability of deep cell morphology in directional solidification is studied.By using the multiple variable method and the matching asymptotic methodandby finding the mode solution of the system,the dispersion relation satisfied by the change rate of the disturbance amplitude of the cell-crystal interface is derived,and the quantization condition of the interface morphology is obtained.The results show that there are two global instability mechanisms in the directional solidification system with considering the growth of deep cell crystal with inter facial dynamic parameters:global oscillation instability mechanism and low-frequency instability.The stability analysis shows that the interface stability parameter εis related to the cell relative parameter λ_(0),and that the larger the interface dynamic parameter M_(*),the larger the stable region of the overall fluctuation instability of the dendrite structure in the overall oscillation modeis.