一种新型潜热处理模型显微偏析数值模拟的应用

Application of a New Model for Latent Heat Treatment to Simulation on Microsegregation

在显微偏析数值模拟中,宏/微观模型通过潜热处理相互耦合。潜热模型直接决定着模拟结果的准确性。将近期先进的潜热处理模型引入显微偏析数值模拟,对Al 4 .5Cu合金铸锭显微偏析的形成进行了数值模拟。在模型中考虑了树枝晶粗化、固相溶质逆扩散、枝晶尖端过冷、随温度变化的溶质扩散系数等动力学因素,微观数值方法中采用变网格技术跟踪移动界面,通过迭代求解溶质扩散方程和溶质守恒方程计算显微偏析参数。在简化耦合算法的情况下,模拟结果与试验结果符合。

Macro and micro models are coupled with each other by latent heat treatment in simulation on microsegregation.The validity of simulation is directly determined by the model for latent heat treatment.A new advanced model for latent heat treatment was introduced into microsegregation models and simulation on microsegregation in the ingot of Al-4.5Cu alloy was carried out.The main kinetic factors influencing microsegregation were accounted for in the modeling including secondary arm coarsening,inverse-diffusion of solid solute,dendrite tip undercooling and variable diffusion coefficient with temperature.The deforming grid technology was applied for tracking the moving interface,and the iterative method was employed for resolving the diffusion equation and solute conservation equation.Simulation results are in good agreement with experimental results based on abbreviated coupling method.