Abstract The metastable immiscible Cu80Fe20 alloys with different diameters were systematically investigated under conventional solidification. Experimental results indicated that the primary and second liquid-liquid phase separation simultaneously occur during solidification. The average size of primary phase-separated Fe-rich spherulites and the interior morphological pattern of minority Cu-rich phase can be greatly influenced by cooling rate due to the dynamic coupling between thermodynamic and kinetic effects. Moreover, various morphological patterns of minority Cu-rich phase in Fe-rich spherulites were observed, which discloses the dynamic evolution process during self-driven second liquid-liquid phase separation. The Marangoni migration, coalescence and coagulation, and Ostwald ripening are the dynamic mechanisms mainly responsible for various morphological patterns of minority Cu-rich phase after phase separation. Such a clear experimental observation of dynamic microstructure evolution for minority Cu-rich phase provides a strong and visualized evidence for the asynchronous crystallization behavior of primary phase-separated Fe-rich spherulites. Phase field simulation was also performed to reveal the dynamic evolution of minority Cu-rich phase during liquid-liquid phase separation. Besides, the experimental Cu80Fe20 alloys exhibit soft ferromagnetic characteristics possessing relatively low coercivity and high saturated magnetization. This present study provides a new strategy to design immiscible alloy with anticipated microstructure possessing tailored properties and desired functionalities.

中文翻译：

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亚稳态不混溶铜铁合金二次液液相分离演化机制的新见解

摘要 系统研究了常规凝固下不同直径的亚稳态不混溶Cu80Fe20合金。实验结果表明，第一次和第二次液-液相分离在凝固过程中同时发生。由于热力学和动力学效应之间的动态耦合，冷却速率可以极大地影响初生相分离的富铁球晶的平均尺寸和少数富铜相的内部形态模式。此外，还观察到了富铁球晶中少数富铜相的各种形态模式，揭示了自驱动二次液-液相分离过程中的动态演化过程。马兰戈尼迁移、聚结和凝结，和 Ostwald 熟化是主要负责相分离后少数富铜相的各种形态模式的动态机制。这种对少数富铜相动态微观结构演化的清晰实验观察为初生相分离富铁球晶的异步结晶行为提供了强有力的可视化证据。还进行了相场模拟，以揭示液-液相分离过程中少数富铜相的动态演变。此外，实验中的 Cu80Fe20 合金表现出软铁磁特性，具有相对较低的矫顽力和高饱和磁化强度。本研究为设计具有预期微观结构的不混溶合金提供了一种新策略，该合金具有定制的性能和所需的功能。