|About this Abstract
||Materials Science & Technology 2012
||International Symposium on Defects, Transport and Related Phenomena
||First-Principles Density Functional Theory Study of Grain Boundary Diffusion in Alpha-Al2O3 Crystal
||Guofeng Wang, Yu Gong
|On-Site Speaker (Planned)
Alumina (Al2O3) is a thermally grown oxide that efficiently enables the alumina-forming alloys to withstand high operating temperatures and oxidizing environments. The growth of alumina scale is closely related to the diffusion process of oxygen and aluminum in the material. To acquire knowledge of diffusion mechanisms and predict diffusion coefficients, we have calculated all the involved energetics about the O and Al diffusion through the grain boundaries of Al2O3 using first-principles density function theory method. In this study, we examined specifically the diffusions of O and Al via vacancy exchange mechanism along low-energy Σ 3 (10-10) grain boundary and high-energy Σ 3 (0001) grain boundary. It was found that both the vacancy formation energy and diffusion activation energy were significantly lower on the grain boundaries than inside the bulk materials. Moreover, the atomic diffusion was predicted to be much faster along the high-energy grain boundaries than the low-energy grain boundaries.