An Atomistic Investigation of the Inverse Coarsening Process by the Phase-Field Crystal Model.

Coarsening is a very common phenomenon that has a crucial impact on the average grain size and properties of materials. However, our current understanding of coarsening is mainly based on the mean-field theories or ex situ observations, and the influence of transient process-related phenomena, such as grain rotation, inverse growth, etc., on coarsening was not considered. In this work, we simulated the coarsening process of supported nanograins by a phase-field crystal (PFC) model. Our simulations show that the inverse coarsening phenomenon might occur under the influence of the substrate, where small grains grow at the expense of the large ones. We found that the substrate-induced grain rotation has a significant effect on the appearance of inverse coarsening, and the average size growth velocity of inverse coarsening is far slower than that of normal coarsening. Furthermore, the influences of initial grain size, misorientations, pinning potential strength, and the lattice mismatch on the coarsening of biocrystal systems are discussed in detail.