Metastable liquid phase separation in undercooled molten Pd_40.5Ni_40.5P₁₉

Abstract

It was demonstrated that molten Pd_40.5Ni_40.5P₁₉ undergoes liquid state phase separation in the undercooling regime δT = T ₁ − T where T ₁ is the liquidus of Pd_40.5Ni_40.5P₁₉ and T is the kinetic crystallization temperature. Liquid state phase separation by nucleation and growth takes place for δT ≤ 60 K while that by spinodal decomposition occurs for δT ≥ 100 K. Microstructural analysis of the undercooled specimen obtained in the undercooling regime of 60 ≤ δT ≤ 100 K indicates that it is the transition regime. Finally, it was found that when undercooled molten Pd_40.5Ni_40.5P₁₉ undergoes liquid state spinodal decomposition, it first decomposes into two liquid networks, which is finally replaced by a system of three liquid networks.