超常条件下Fe-Cu基难混溶合金的快速凝固机理研究

Liquid alloys can be highly undercooled and then rapidly solidified under extraordinary conditions such as free fall and glass fluxing. The microstructural characteristics and solidification mechanisms are different from those under conventional conditions. In this project, the dendritic growth, microstructural evolution and solute distribution of liquid Fe-Cu-Si and Fe-Cu-Ge immiscible alloys are systematically investigated by drop tube, glass fluxing and melt spinning techniques. The segregation characteristics of microstructural morphology under normal gravity and microgravity conditions are systematically analyzed to explore the underlying mechanisms of liquid phase separation within immiscible alloys. The surface nucleation and solid-liquid interface migration is studied to analyze the dynamic mechanism of rapid dendritic growth within immiscible alloys. The phase constitution, solidification microstructure and solute distribution of rapidly solidified alloys are deeply analyzed to reveal the rapid solidification mechanisms of ternary Fe-Cu-based immiscible alloys.

在自由落体过程和熔体浸浮状态等超常条件下，液态合金可获得深过冷进而实现快速凝固，组织特征及形成机理将与传统凝固显著不同。本项目采用自由落体、熔体浸浮以及熔体急冷三种超常凝固技术，实现液态Fe-Cu-Si和Fe-Cu-Ge难混溶合金的快速凝固，研究其凝固过程中的枝晶生长、组织演化以及溶质再分配等规律。系统分析重力与微重力条件下合金的液相分离特征，探索难混溶合金的液相分离机理。实时监测深过冷条件下合金熔体的表面形核及固液界面迁移，阐明难混溶合金中的快速枝晶生长动力学机制。深入研究快速凝固合金的相组成、组织形貌和溶质分布特征，揭示三元Fe-Cu基难混溶合金的快速凝固机理。