抽拉速度对Ti-45Al合金定向凝固组织演化影响的数值模拟

Numerical Simulation of Effect of Pulling Velocity on Structure Evolution During Directional Solidification of Ti-45Al Alloy

采用基于溶质扩散控制模型结合CA方法对Ti-45Al合金定向凝固过程中抽拉速度对显微组织演化影响进行数值模拟。结果表明,随抽拉速度增加,凝固形态经历了平面→胞晶→胞/枝混合结构→树枝晶的转变,如果温度梯度高于20K/mm,仅经历平面→胞晶转变。此外,将模拟结果与实验结果和理论分析进行对比,证明了模型的有效性。

The structure evolution of Ti-Al alloy during directional solidification was simulated to investigate the effects of the velocity by applying a solute diffusion controlled solidification model with Cellular Automation （CA）, and the results have showed that with increasing pulling velocities, the morphology of the interface varies from plane to cell, to the mixed structure of cell and dendrite, finally to dendrite, while with thermal gradient GL〉20 K/mm, the morphology of the interface only varies from plane to cell. In addition, simulated results were compared with eXperimental and theoretical analysis results, which testified the accuracy of the model.