Zener Pinning through Coherent Precipitates: A Phase Field Study

TL;DR

This paper introduces a phase field model to analyze how coherent precipitates influence Zener pinning of grain boundaries, revealing that elastic properties and precipitate shape significantly affect pinning efficiency.

Contribution

The study develops a novel phase field model incorporating elastic effects to understand coherent precipitate influence on Zener pinning, highlighting the impact of elastic inhomogeneity and anisotropy.

Findings

Increased elastic misfit accelerates precipitate coarsening.

Needle-shaped precipitates are less effective in Zener pinning.

Elastic anisotropy leads to needle-shaped precipitates.

Abstract

A novel phase field model has been developed to study the effect of coherent precipitate on the Zener pinning of matrix grain boundaries. The model accounts for misfit strain between precipitate and matrix as well as the elastic inhomogeneity and anisotropy between them. The results show that increase in elastic misfit, elastic inhomogeneity, and elastic anisotropy increases the coarsening rate of the precipitates. Increased coarsening of precipitates in turn decreases the pinning of grain boundaries. Therefore, increase in misfit strain, elastic inhomogeneity and anisotropy negatively affect the Zener pinning through coherent precipitate. This study shows elastic anisotropy gives rise to the needle shape precipitate. It has also been shown that these needle shaped precipitates are not very effective in Zener pinning. This study provides an understanding into the effect of coherent precipitate on the Zener pinning of matrix grain boundaries.