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基于Jackson和Hunt二元规则共晶稳态生长理论,在共晶两相的界面溶质守恒条件中引入密度修正项,改进了共晶两相的界面溶质守恒条件.在此基础上,根据二元层片共晶常规凝固过程中层片组织稳态生长时Gibbs自由能的变化,运用极值形态选择原理确定二元层片共晶凝固过程中层片间距特征尺度选择准则.理论分析表明,对于给定二元共晶合金,在常规凝固条件下的层片间距选择通常为一有限区间.此外,理论分析还表明,二元层片共晶稳态生长时其特征尺度的选择可以呈现超稳定性,而且在给定的凝固条件下超稳定性只和给定合金系的物性参数有关.将该形态选择准则分别运用于物性参数精确已知的Al-Al2Cu,Sn-Pb和CBr4-C2Cl6合金系,表明计算结果与实验结果相符合.
Based on Jackson and Hunt binary eutectic eutectic steady state growth theory, the density correction term is introduced into the solute conservation condition at the interface of eutectic and two phases to improve the interface solute conservation condition of eutectic two phases. On this basis, The change of Gibbs free energy during the steady-state growth of the lamellar eutectic during the eutectic process of the lamellar eutectic, and the principle of the extremum morphology selection is used to determine the selection criterion of the eigenvalue of the lamellar spacing during the eutectic solidification of the binary lamellae. The theoretical analysis shows that for the given In the binary eutectic alloy, the choice of layer spacing under conventional solidification conditions is usually a finite interval. In addition, the theoretical analysis also shows that the eigen-scale selection of the eutectic in the binary ply growth can be super-stable, Moreover, the super-stability under a given solidification condition is only related to the physical parameters of a given alloy system.The morphology selection criteria are respectively applied to the Al-Al2Cu, Sn-Pb and CBr4-C2Cl6 alloys with well-known physical properties, The results show that the calculated results are consistent with the experimental results.