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本文考察了 Al—Cu 合金凝固体系液固界面自发地由非平衡态向平衡过渡的过程;并研究了冷却速率对开始结晶时溶质分配的影响。结果表明,随着在结晶温度保温时间的延续,表征着实际溶质分配系数 K 对平衡偏离程度的 lnK/K_0值以指数规律衰减并趋近于零。同时还发现随凝固过程冷却速率的增加实际溶质分配系数 K对 K_0的偏离加大。
In this paper, we investigate the spontaneous transition from non-equilibrium to equilibrium in liquid-solid interface of Al-Cu alloy solidification system and study the influence of cooling rate on the solute distribution when starting crystallization. The results show that the lnK / K0 value of the actual solute partition coefficient K to the degree of equilibrium deviation decays exponentially and approaches zero as the holding time of the crystallization temperature continues. At the same time, it is also found that the actual solute partition coefficient K increases the deviation of K_0 with the increase of the cooling rate during solidification.