铝基梯度复合材料凝固过程耦合数值模拟及实验研究

Coupling Simulation and Experimental Validation on Solidification of Al Matrix Functionally Graded Materials

离心铸造颗粒增强铝基梯度复合材料流动场的数值模拟将基体粘度设为定值不合实际。为此设想将基体的粘度值设置为温度函数,并结合实验得到温度-粘度近似函数。模拟计算铸件的温度场,测量开始每一时间步的瞬时温度场,通过温度-粘度函数计算粘度场,得到瞬时流动场。这种耦合方法预测凝固期间颗粒体积分数与实际结果更具契合性。

Matrix viscosity as constant does＇nt tally with fact when the flow field of particle reinforced aluminiurn matrix graded material during centrifugal casting is simulated. But actually matrix viscosity should be considered as a function of temperature. An experimental viscosity-temperature function was gotten. Simulating temperature field, measuring the instantaneous temperature field at the beginning of each time step, viscosity field was computed using viscosity-temperature function. Then the instantaneous flow field was obtained. This coupling model prediction of particle volume fraction distribution during solidification is validated against the experimental results, which shows its better agreement with the practice.