Impact of grain boundary energy anisotropy on grain growth

TL;DR

This paper presents a simulation model that incorporates anisotropic grain boundary energy to more accurately replicate microstructural evolution during grain growth in polycrystalline Ni, revealing phenomena not captured by isotropic models.

Contribution

The study introduces a threshold dynamics model accounting for anisotropic grain boundary energy, improving the realism of grain growth simulations without modifying the energy minimization algorithm.

Findings

Relative areas of low-energy twin boundaries increase during growth

Average grain boundary energy decreases as grains grow

Higher-energy boundaries decrease in population during growth

Abstract

A threshold dynamics model of grain growth that accounts for the anisotropy in the grain boundary energy has been used to simulate experimentally observed grain growth of polycrystalline Ni. The simulation reproduces several aspects of the observed microstructural evolution that are not found in the results of simulations assuming isotropic properties. For example, the relative areas of the lowest-energy twin boundaries increase as the grains grow and the average grain boundary energy decreases with grain growth. This decrease in energy occurs because the population of higher-energy grain boundaries decreases while the population of lower-energy boundaries increases as the total grain boundary area decreases. This phenomenon emerges from the assumption of anisotropic grain boundary energies without modification of the energy minimizing algorithm. These findings are consistent with the observation that, in addition to the decrease in grain boundary area, additional energy is dissipated during grain growth by a decrease in the average grain boundary energy.