Liquid-liquid phase separation in immiscible Cu-Co alloy

In this study, the solidification pathways and the generation of nano-sized Co-rich phase in metastable immiscible Cu-Co alloys with different undercoolings were systematically elucidated. For undercooling above the metastable miscibility gap, solidification commenced in a normal way with the nucleation and growth of primary α-Co dendrites. For undercooling below the metastable miscibility gap, primary LLPS and even secondary LLPS took place. Nano-sized Co-rich phase was found to be easy precipitated from the Cu-rich phase after solidification in both cases. The results provide a possibility for the adjustment of immiscible alloys possessing desired properties by nano-sized phases.