Al固/液界面动力学因子和动力学行为

Solid/Liquid Interfacial Dynamic Coefficient and Dynamic Behavior of Al

从固/液界面的动力学方程出发,通过设计不同的计算模型,系统地研究了平面型界面和圆柱型界面的动力学行为,并计算了固/液界面的动力学因子(μ)。模拟平面型界面的运动和涨落行为,并分别提取了μ,两种模拟给出的结果非常接近,都有:μ100>μ110>μ111。模拟平面型界面回复现象,当界面偏离平衡位置时,会在界面张力的作用下发生回复,界面形貌在回复过程满足Gauss衰减规律。模拟圆柱型短晶核的界面运动行为,发现晶核在凝固或熔化过程中,晶核半径的变化速度逐渐加快,但存在一个函数,变化速度为匀速。研究了圆柱型长晶核的熔断行为,解释了界面涨落导致晶核熔断的内在机制,并发现熔断断口形貌近似服从Gauss分布。

Different models were designed according to the solid/liquid interfacial dynamic equations, the dynamic behavior of the flat and cylindrical interface was explored and the dynamic coefficients （/z） of the solid/liquid interfaces were calculated. First, the dynamic coefficient was extracted from the simulation of fiat interface movement and fluctuation. The results from the two models were close, and the order of dynamic coefficients wereμ100 〉μ110 〉μ111. Second, it was found that the interface would return when deviated from equilibrium position in the effect of interfacial free energy, and the morphology of interface followed Gaussian decay laws. Moreo- ver, the movements of cylindrical interface were simulated for solidification and mehing. The radius increased or decreased with a grow- ing speed and there was a linear relationship between a certain function about the radius and time. At last, the rupture of long cylindri- cal nucleus was studied, and was explained by interfacial fluctuation. It was found that the morphology of fracture followed Gaussian distribution approximately.