Incorporating density jumps and species-conserving dynamics in XPFC binary alloys

TL;DR

This paper develops an advanced phase-field-crystal model for binary alloys that accounts for density differences, conserved dynamics, and pressure control, enabling detailed simulation of microstructural processes during solidification.

Contribution

It introduces a consistent formulation of the XPFC model for binary alloys with density jumps and conserved dynamics, and enhances pressure control for simulating microstructural phenomena.

Findings

Model accurately describes phases with unequal densities.

Pressure control influences grain boundary and phase behaviors.

The model captures microstructural evolution during solidification.

Abstract

This work presents a consistent formulation of the structural phase-field-crystal model of substitutional binary alloys that allows for the description phases of unequal densities, a key feature in solidification. We further develop the dynamics of the model to be consistent with conserved Langevine dynamics in the true governing species densities. Additionally, this work expands on the ability to control pressure, so far only implemented in pure materials, to binary alloys by improving the control system that controls pressure from previous work. We study the equilibrium properties of the new model, and demonstrate that control of pressure can drive various kinematic microscopic processes in materials such as grain boundary pre-melting, phase instability, and grain or inter-phase boundary motion.