Effect of Grain Boundary on Spinodal Decomposition Using the Phase Field Crystal Method

Spinodal decomposition (SD) with different grain boundaries (GBs) is investigated on the atomic scale using the novel phase field crystal model. It is demonstrated that the decomposition process is initiated by precipitating one phase with a larger lattice constant in the tension region at the GBs and the other one with a smaller lattice constant in the compression region. As the phase separation proceeds, the dislocations comprising the low-angle GBs migrate toward the compositional domain boundaries to relieve the coherent strain energy, and eventually become randomly distributed in the coarsening regime of SD, which leads to the disappearance of the low-angle GBs. For high-angle GBs, the location of GBs remains unchanged, while the atoms rearrange along the GBs to fit the stress field arising from compositional inhomogeneity.