Grain-boundary grooving and agglomeration of alloy thin films with a slow-diffusing species

TL;DR

This paper introduces a phase-field model to study how slow-diffusing species influence grain-boundary grooving and agglomeration in alloy thin films, revealing diffusion path changes that affect grooving rates and agglomeration times.

Contribution

It develops a general phase-field model that captures the effects of slow-diffusing species on grain-boundary grooving and agglomeration, highlighting diffusion path transitions.

Findings

Slow species concentrate near groove tips, limiting grooving.

Diffusion path shifts from boundary to parallel with substrate over time.

Model suggests strategies for designing agglomeration-resistant thin films.

Abstract

We present a general phase-field model for grain-boundary grooving and agglomeration of polycrystalline alloy thin films. In particular, we study the effects of slow-diffusing species on grooving rate. As the groove grows, the slow species becomes concentrated near the groove tip so that further grooving is limited by the rate at which it diffuses away from the tip. At early times the dominant diffusion path is along the boundary, while at late times it is parallel to the substrate. This change in path strongly affects the time-dependence of grain boundary grooving and increases the time to agglomeration. The present model provides a tool for agglomeration-resistant thin film alloy design. keywords: phase-field, thermal grooving, diffusion, kinetics, metal silicides