(1. 湖南大学 汽车车身先进设计制造国家重点实验室，长沙 410082；2. 湖南大学 机械与运载工程学院，长沙 410082)
摘 要: 采用改进的Miedema模型和Eyring模型，对Al-2%Cu合金的液相扩散系数进行理论计算，建立了二元合金液相扩散系数的理论计算模型，解决实验难以测量液相扩散系数导致数据匮乏的难题。在Eyring模型中，引入液态合金黏度—时间的变化曲线，替代原模型中的溶剂黏度数值，以进一步提高计算结果的准确性。在微观组织模拟中，基于常规恒定液相扩散系数模拟结果的柱状晶比例为20.1%，而基于本研究计算所得的液相扩散系数曲线模拟结果的柱状晶比例为64.8%，更接近实验测得的柱状晶比例58.1%，很好地验证了液相扩散系数理论计算模型的可行性和准确性。
关键字: Al-Cu合金；Miedema模型；Eyring模型；扩散系数；微观组织
（1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China; 2. College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China）
Abstract:The liquid phase diffusion coefficient of Al-2%Cu alloy was calculated with the modified Miedema model and Eyring model, to further improve the accuracy. The mathematical model of liquid phase diffusion coefficient in binary alloy was established to resolve the lack of liquid phase diffusion coefficient data that are difficult to measure in the experiment. Instead of the solvent viscosity value, the viscosity—temperature curve of liquid alloy was introduced into the Eyring model to increase the accuracy of calculation. In the microstructure simulation, the simulated proportion of columnar grains based on the normal constant liquid phase diffusion coefficient is 20.1%; while the proportion of columnar grains based on the calculated liquid phase diffusion coefficient with the developed model is 64.8%, which is much closer to the experimental result of 58.1%, indicating that the mathematical model of liquid phase diffusion coefficient is feasible and accurate.
Key words: Al-Cu alloy; Miedema model; Eyring model; diffusion coefficient; microstructure
