论文部分内容阅读
以扩展不可逆热力学为基础,针对非平衡凝固过程中界面前沿液相中非平衡溶质扩散造成的弛豫效应,对界面稳定性动力学M-S理论进行了修正.发现在稳态条件下弛豫效应改变液相中的浓度场,因而影响界面的稳定性.通过界面前沿液相溶质浓度与温度的耦合关系,综合考虑动力学过冷度以及与固液界面移动速率相关的液相线斜率等动力学因素的影响,进而得到适用于非平衡凝固的平界面稳定性判据.结果表明平界面的稳定性受与固液界面移动速率相关的液相线斜率影响,但与动力学过冷度无关.
Based on the extension of irreversible thermodynamics, the MS theory of interfacial stability is modified to deal with the relaxation effect caused by the non-equilibrium solute diffusion in the liquid front of the interface during the non-equilibrium solidification. It is found that the relaxation effect changes under steady-state conditions The concentration field in the liquid phase, thus affecting the stability of the interface.Based on the coupling relationship between the liquid solute concentration and temperature in the front of the interface, the kinetic undercooling and the kinetics of the slope of the liquidus, which is related to the moving velocity of the solid-liquid interface, And then get the criterion of flat interface stability suitable for non-equilibrium solidification.The results show that the stability of the flat interface is affected by the slope of the liquidus, which is related to the moving velocity of the solid-liquid interface, but not with the dynamic undercooling.