Modeling Melting in Binary Systems

TL;DR

This paper introduces a coarsened model for binary systems with limited miscibility, capturing phase transitions including melting and compositional changes, using a structural state approach to describe thermodynamics qualitatively.

Contribution

It proposes a novel structural state-based model for binary systems that accounts for multiple phase transitions, including melting and compositional phase changes.

Findings

The model qualitatively reproduces key features of binary phase diagrams.

It identifies two distinct phase transitions: orientation order-disorder and compositional.

The approach provides insights into melting behavior in binary alloys.

Abstract

A coarsened model for a binary system with limited miscibility of components is proposed; the system is described in terms of structural states in small parts of the material. The material is assumed to have two alternative types of crystalline local arrangements associated with two components of the alloy. Fluctuating characteristics of a cluster are the type and the space orientation of its crystalline arrangement. There are two different phase transitions in the model system, an orientation order-disorder transition representing melting, and a phase transition between phases differing in concentration of components. Depending on the parameters characterizing the interaction in the system, this last transition may take place both in the crystalline and in the amorphous (molten) phase. A special approximation is used to study the thermodynamics of the system. The calculated phase diagram describes, at least qualitatively, the most important features of a binary system.