Grain-Growth Stagnation from Vacancy-Diffusion-Limited Disconnection Climb

TL;DR

This paper identifies vacancy-diffusion-limited disconnection climb as the fundamental microscopic mechanism causing grain-growth stagnation in polycrystals, linking vacancy transport to microstructural evolution.

Contribution

It introduces a phase-field crystal model extended for vacancy diffusion to elucidate the microscopic origin of grain-growth stagnation.

Findings

Disconnection climb rates correlate with grain size at growth arrest.

Vacancy diffusion governs disconnection dynamics and grain growth behavior.

The model links vacancy transport to microstructural evolution.

Abstract

Grain growth in polycrystals typically stagnates at long times. We identify disconnection climb, limited by vacancy diffusion, as a fundamental microscopic mechanism underlying this behavior. Using a phase-field crystal framework extended to model vacancy diffusion, we resolve grain-boundary migration on diffusive time scales and show that disconnection climb rates correlate with the characteristic grain size at which growth arrests. These results link vacancy transport, disconnection dynamics, and microstructural evolution, establishing vacancy diffusion as a key governing factor.