|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||First-Principles Computational Study of Charged Vacancy Diffusion in Alpha-Al2O3 and Alpha-Cr2O3
||Guofeng Wang, Yinkai Lei, Corinne M Gray
|On-Site Speaker (Planned)
Alumina (Al2O3) and chromia (Cr2O3) are thermally grown oxides that efficiently enable alloys to withstand high operating temperatures and oxidizing environments. The functionality of these oxide scales are closely related to the diffusion process of ions. To acquire knowledge of diffusion mechanisms and predict diffusion coefficients, we have calculated the energies of charged vacancies diffusion through the bulk crystal and grain boundaries of Al2O3 and Cr2O3 using the first-principles density functional theory method. In this study, we predict that the migration energy of vacancy diffusion strongly depends on the charge state of the vacancy involved. Importantly, we reveal that this charge-dependent vacancy diffusion in alumina/chromia is directly related to the electron occupancy and energy level change of the defect states of the charged vacancy. Moreover, we predict that the addition of reactive elements to the scales would reduce the ion diffusion due to both blocking effect and electronic effect.
||Planned: Supplemental Proceedings volume