任意固相反扩散条件下枝晶凝固溶质传输微观/宏观模型化

MICRO-/MACRO-SCOPIC MODELING OF SOLUTAL MASS TRANSPORT IN DENDRITE SOLIDIFICAfION WITH PARTIAL SOLID BACK DIFFUSION

通过对合金枝晶凝固中有任意固相反扩散条件下微观溶质再分布的模型化，扩展了作者提出的合金凝固传输及宏观偏析连续介质模型本文微观／宏观统一模型提出的归一化固相反扩散集合参数除了包括合金的团相扩散系数外，还包含了生长枝晶尺度及几何形态参数、凝固速率和溶质分配系数等影响因素模型的数值计算结果表明。

The continuum model proposed by the present authors for macroscopic solidification transport phenomena and macrosegregation formation was extended to account for the effect of any incomplete solid back diffusion through a microscopic dendrite solidification model. A generalized coefficient for the solid back diffusion was proposed by the present microscopic/macroscopic model, which includes the growing dendrite dimension, the parameters for the dendrite geometry, the solidification rate and partition coefficient etc besides the solid diffusivity.Numerical simulation of macrosegregations in a horizontal directionally soliditied A1-4.4Cu ingot with assumed different solid diffusivities of the copper solute was performed using the extended continuum model. The computation results show that the variation of the solid back diffusion can evidently influence the macrocomposition distribution in the soliditied ingot, and the greater the solid solute diffusivity, the lighter the macrosegregation seventy.