Effect of Initial Composition on the Liquid–Solid Phase Transition in Cr–W Alloy Nanoparticles

Abstract

Phase transformations in nanoscale systems are influenced by a variety of different factors. In this study, we use methods of equilibrium chemical thermodynamics to demonstrate that the initial composition of a nanosystem is among such factors and model the influence of initial composition on the phase diagram of Cr–W nanoparticles in the two-phase region between their liquidus and solidus temperatures. We show that the equilibrium compositions of the liquid and solid phases and phase transition temperatures depend on the initial composition of the nanoparticles. At any composition, the liquidus temperature of a nanoparticle is lower than that of a corresponding macroscopic system. The solidus temperature of a nanoparticle can be both lower and higher than that of a corresponding macroscopic system, depending on composition. As the particle size decreases to the nanometer range, the temperature range of the heterogeneous region narrows down.