Efficient and quantitative phase field simulations of polycrystalline solidification using a vector order parameter

TL;DR

This paper introduces a vector order parameter phase field model derived from a grand potential functional for efficient, quantitative simulation of polycrystalline solidification, capturing grain growth, boundary energies, coarsening, and nucleation.

Contribution

The paper presents a novel vector order parameter model based on a grand potential functional, enabling comprehensive and efficient simulation of polycrystalline solidification phenomena.

Findings

Accurately reproduces dendritic growth in binary alloys.

Quantitatively matches grain boundary energies and solute back-diffusion.

Demonstrates nucleation modeling via thermal fluctuations.

Abstract

A vector order parameter phase field model derived from a grand potential functional is presented as a new approach for modeling polycrystalline solidification of alloys. In this approach, the grand potential density is designed to contain a discrete set of finite wells, a feature that naturally allows for the growth and controlled interaction of multiple grains using a single vector field. We verify that dendritic solidification in binary alloys follows the well-established quantitative behavior in the thin interface limit. In addition, it is shown that grain boundary energy and solute back-diffusion are quantitatively consistent with earlier theoretical work, with grain boundary energy being controlled through a simple solid-solid interaction parameter. Moreover, when considering polycrystalline aggregates and their coarsening, we show that the kinetics follow the expected parabolic growth law. Finally, we demonstrate how this new vector order parameter model can be used to describe nucleation in polycrystalline systems via thermal fluctuations of the vector order parameter, a feature which has been thus far lacking from multi-phase or multi-order parameter based phase field models. The presented vector order parameter model serves as a practical and efficient computational tool for simulating polycrystalline materials. We also discuss the extension of the order parameter to higher dimensions as a simple method for modeling multiple solid phases.