Revealing curvature and stochastic effects on grain growth kinetics: A thermodynamic perspective from the extremal principle

TL;DR

This paper extends the thermodynamic framework of grain growth by incorporating curvature and stochastic effects through the extremal principle, resulting in a new mean-field model that aligns well with simulation data.

Contribution

It introduces a thermodynamic-based mean-field model for grain growth that accounts for curvature and stochastic effects, enhancing understanding of microstructure evolution.

Findings

The model accurately reproduces ultra-large phase-field simulation results.

It explains the roles of curvature and stochastic effects in grain growth thermodynamically.

The framework unifies microstructure entropy and topological interactions under the extremal principle.

Abstract

In the theoretical development of normal grain growth, the roles of "drift" (curvature effect) and "diffusion" (stochastic effect) have been an open question for many years. By coupling contributions of microstructure entropy and grain topological interactions with thermodynamic extremal principle (TEP), this letter extends the existing thermodynamic framework of grain growth. It not only explains the curvature and stochastic effects by thermodynamics but provides a new mean-field model for grain growth. Through thermodynamic modification, this new model can yield a high accuracy representation of existing ultra-large phase-field simulated results.