本文分别利用纯扩散模型、溶质边界层对流模型和强对流Scheil方程对包晶合金定向凝固过程中的带状组织、宏观偏析的形成规律以及对流效应进行系统研究, 详细讨论了对流对包晶合金定向凝固过程中带状组织和宏观偏析的影响规律. 与Fe--Ni包晶合金定向凝固实验结果进行对比发现, 对流强度参数λ在1.7至2之间时溶质边界层对流模型预测结果与感应加热定向凝固实验结果吻合很好, 说明利用该模型可以预测对流较大条件下包晶合金定向凝固过程中的组织演化和轴向宏观偏析.
The axial macrosegregation and relevant microstructure evolution of Fe–Ni peritectic alloys directionally solidified under different convection strength were discussed using pure diffusion model, boundary layer convection model and the Scheil equation. Comparing with the experiments of Fe–Ni alloys conducted in resistance heating and induction heatinBridgman system, it was found that the predictions of boundary layer convection model areed well with the experimental results of induction heating drectional solidification when the convection strength parameters lies in the region 1.7<λ≤2, indicating that the model can be used to predict the axial macrosegregation and microstructures evolution of peritectic alloys.
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