Cell dynamics modeling of phase transformation and metastable phase formation

TL;DR

This paper models the kinetics of phase transitions in three-phase systems using a cell dynamics approach, revealing scenarios of metastable phase formation and kinetic arrest.

Contribution

It introduces a simple phasefield model with a single order parameter capable of simulating three-phase coexistence and transition kinetics.

Findings

Identification of dynamical and kinetically arrested static scenarios

Demonstration of metastable phase formation during phase transitions

Discussion of various kinetic scenarios in three-phase systems

Abstract

The phase transition kinetics in three phase systems was investigated using the numerically efficient cell dynamics method. A phasefield model with a simple analytical free energy and single order parameter was used to study the kinetics and the thermodynamics of a three-phase system. This free energy is able to achieve three phases coexistence, which for simplicity we call \alpha, \beta and \gamma phases. Our study focused on the kinetics of phase transition rather than the nucleation of a seed of a new phase that was introduced into the matrix of the old phase when the relative stability of the three phases were changed. We found dynamical as well as kinetically arrested static scenarios in the appearance of the macroscopic metastable phase. A few other interesting scenarios of the kinetics of phase transition in this three-phase system will be demonstrated and discussed.