摘要
基于溶质扩散和界面能的作用,考虑成分过冷、曲率过冷和界面能各向异性和界面扰动,并改进了溶质再分配的算法以及界面液相浓度偏导数的离散格式,建立了凝固过程中晶体的生长模型。利用此模型并采用元胞自动机方法对铝合金定向凝固过程中的平界面、胞状和枝晶状3种典型界面形貌演化进行了模拟,并把模拟参数和模拟结果与经典凝固理论进行了比较,发现在G/V值略小于成分过冷判据给出的临界值时就已经获得平界面。并验证了平均一次枝晶间距与温度梯度和抽拉速度的变化关系,与理论结果吻合较好。
Based on the physical processes of solute diffusion and interfacial energy,a model of describing crystal growth was developed with the improvement of algorithm of solute redistribution and the improved discretization scheme of partial derivative of liquid concentration at the interface,including the effects of constitutional undercooling,curvature undercooling,anisotropy of interfacial energy and perturbation on the interface.By using this model,cellular automata method was adopted to simulate the morphology evolution of the three typical interface including planar,cellular and dendritic in aluminum alloy directional solidification.By comparing the simulation parameters and results of this model with the classical solidification theory,it was discovered that the planar interface was formed when the G /V value was slightly smaller than the critical value given by constitutional undercooling criterion.The variation relationship of the average primary dendrite spacing with the temperature gradient and the drawing velocity were studied and matched well with the theoretical results.
出处
《四川大学学报（工程科学版）》
EI
CAS
CSCD
北大核心
2010年第6期219-226,共8页
Journal of Sichuan University (Engineering Science Edition)
基金
武器装备预研基金资助项目(9140A18070107SC0103)
关键词
定向凝固
元胞自动机
数值模拟
微观组织
directional solidification
cellular automata
numerical simulation
microstructure
