Oxidation is a crucial aspect for the performance and design of metals, especially in high-temperature applications. In the present work, a kinetic Monte Carlo (KMC) model was used to analyze the effects of grain morphology, grain size, and grain configuration on oxidation performance. The model predicted that gradient structures with small grains near the surface helped reduce the oxidation rate by allowing for lateral rather than inward oxide growth. This led to the formation of protective oxide layers near the surface, which slowed additional inward oxygen diffusion. Vertical grains tended to increase the oxidation rate, while horizontally configured grains were found to inhibit oxidation. This is because the vertical grain boundaries (GB) provided fast pathways, enabling deep oxygen penetration of the sample. Our model also showed that triangular grains performed better than circular and square grains of roughly the same size. Finally, diffuse interfaces between the metal and the oxide were found to better inhibit oxygen diffusion compared to sharp interfaces. The results of this work may be useful for informing the manufacturing process of oxidation-resistant metals.
Mysonhimer et al. (Wed,) studied this question.