Recrystallization Mechanisms of Aluminum and Aluminum Oxide Interfaces through Reactive Simulations.

Aluminum and alumina are essential materials used in various energy processes and devices. In this study, we conduct an atomic-level investigation into the microscopic mechanisms that govern the recrystallization (crystal growth from its melt) of aluminum and aluminum oxide interfaces. We utilize a reactive force field (ReaxFF) along with bond-orientational order parameters and unsupervised clustering algorithms to clarify the barrierless nature of the ultrafast metallic growth processes of aluminum. Our analysis provides valuable insights into the microscopic mechanisms that facilitate the incorporation of atoms into alumina, which is a crucial step in the crystal growth of this metal oxide. For the crystal growth of alumina we identify a sequential process where oxygen atoms first occupy lattice sites before aluminum atoms are integrated. This mechanism involves energy barriers that may explain the slow crystal growth rates reported in the crystallization of aluminum oxide. Furthermore, we report a significant correlation between the incorporation of oxygen into the crystal structure and the modification of the atomic charge. These findings enhance our understanding of the distinct crystallization behaviors of metals and metal oxide interfaces, offering microscopic insights for developing materials with improved performance characteristics.