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本文在已有的二元初生相元胞自动机(CA)方法的基础上,针对二元共晶凝固过程提出了改进的元胞自动机(MCA)模型.该模型考虑成分过冷和曲率过冷对界面形态的影响,通过界面溶质浓度守恒来获得共晶α相和β相生长速率,模拟了层片的湮灭、分叉与稳态生长.为了验证模型的可靠性,对常见的CBr_4-C_2Cl_6共晶透明合金进行了模拟,研究了抽拉速率对共晶层片间距大小的影响,模拟结果与文献中的实验结果吻合良好;同时模拟了共晶层片间距调整过程的形貌演化以及层片振荡不稳定性现象.本文将MCA模型扩展到三维定向凝固过程中,研究了共晶形态的层棒状转变机制.
In this paper, an improved cellular automata (MCA) model is proposed for the binary eutectic solidification process based on the existing dual-phase cellular automata (CA) method. The model considers the component supercooling and curvature Cold and cold on the interface morphology, the eutectic α phase and β phase growth rate were obtained through the conservation of interface solute concentration, and the annihilation, bifurcation and steady state growth of the ply were simulated.In order to verify the reliability of the model, the common CBr_4- C_2Cl_6 eutectic transparent alloys were simulated to study the effect of drawing rate on the eutectic layer spacing. The simulation results are in good agreement with the experimental results in the literature. Simultaneously, the morphological evolution of the eutectic layer spacing adjustment process was simulated. In this paper, MCA model is extended to three-dimensional directional solidification process, and the layer-rod transition mechanism of eutectic morphology is studied.