(1. 哈尔滨工业大学 现代焊接生产技术国家重点实验室，哈尔滨 150001；2. 南京航空航天大学 材料科学与技术学院，南京 210016)
摘 要: 基于元胞自动机方法构建了枝晶生长数值模型，并将其应用于Al-Cu二元合金凝固过程的模拟。在该模型中，枝晶尖端生长速度模型基于溶质守恒建立。模拟过程中重点考虑不同冷却速率及形核条件对柱状树枝晶形态与溶质偏析的影响。计算结果表明，凝固过程中溶质易于富集在枝晶臂之间的封闭或半封闭区域。同时，随着冷却速率加大，晶界偏析变得更为显著。形核密度在一定程度上影响着枝晶形态，特别是影响着二次和三次枝晶的生长。
关键字: 枝晶生长；数值模拟；元胞自动机
（1. State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China;2. School of Materials Science and Technology, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China）
Abstract:A dendrite grain growth model that is based on cellular automaton method was developed and applied to simulate the columnar dendrite grain growth during the directional solidification process of Al-Cu binary alloys. And the velocity model was based upon the solute conservation at the solid/liquid interface. The influences of different cooling speeds and different nucleation conditions on the dendrite morphologies and solute segregation were considered. The results indicate that the solute of high concentration liquids is easy to concentrate in the closed or semi-enclosed zones among secondary or tertiary dendrite arms. The grain boundary segregation becomes more severe when the cooling speed is increased. At the same time, the nucleation density affects the dendrite morphologies, especially the growth of secondary and tertiary dendrite arms.
Key words: dendrite growth; numerical simulation; cellular automaton
