利用溶质扩散控制模型对TiAl合金柱状晶/等轴晶转变过程进行了数值模拟,结果表明,等轴晶在柱状晶前沿形核及生长过程中,当两个扩散场相遇时,观察到成分冲击波,它可能是导致柱状晶停止生长的一个主要原因.利用该模型,对小铸件柱状晶/等轴晶转变过程进行了预测,在模拟过程中发现柱状晶界面前沿液相温度梯度,成分过冷度可联合对柱状晶/等轴晶转变产生影响,模拟与实验观察符合较好. The numerical simulation of columnar / equiaxed transformation of TiAl alloy was performed by using solute diffusion control model. The results show that during the nucleation and growth of equiaxed grains, when the two diffusion fields meet each other, the component shock waves , Which may be one of the main reasons leading to the stop of columnar crystal growth.Using the model, the process of columnar / equiaxed crystal transition of small castings is predicted, and the liquidus temperature gradient in front of columnar grain boundary is found in the simulation process, Degree can be combined on the columnar / equiaxed transformation, simulation and experimental observations in good agreement.