Motivation

Early studies suggested that specific grain boundaries significantly influence the overall properties of materials, implying that material performance could be improved through intentional grain boundary engineering. For instance, twin boundaries have been shown to markedly enhance material properties. Given that grain boundaries possess five degrees of freedom and the current methods to incorporate both misorientation and inclination dependencies are either lacking or difficult to implement, further research and advanced modeling techniques are necessary.

Design

A previously developed Spherical-Gaussian Method (https://doi.org/10.1016/j.commatsci.2020.110126) is used to incorporate 5-D anisotropy in two phase field models originally published by Moelans (https://doi.org/10.1016/j.matdes.2022.110592), here named epsilon and gamma models. Quaternions, assigned to individual grains as orientations and used to compute quaternion misorientations at each grain boundary, drive the ongoing mesoscale changes. As a means of incorporating the effects of specific low energy boundaries, such as twin boundaries, local minima/specific grain boundaries are stored as minima library for use in the phase field models through a developed gaussian switch (https://doi.org/10.1186/s41313-021-00035-3)
(https://doi.org/10.1016/j.jcrysgro.2023.127508).

New material objects that add anisotropy to grain boundary energy and mobility using the Spherical-Gaussian Method were created as well as the kernels necessary to drive grain growth. They have been tested for bicrystal and tricrystal simulations with future possibilities for polycrystalline simulations.

Impact

Enable the simulation of more accurate modeling of anisotropic grain growth.