About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Interstitial–Metal Interactions: The Outsized Role of Small Atoms
|
| Presentation Title |
Effects of Oxygen Interstitials on Vacancy Mobility in Refractory Metals and Alloys |
| Author(s) |
Pravendra Patel, Liang Qi |
| On-Site Speaker (Planned) |
Pravendra Patel |
| Abstract Scope |
Oxygen is an unavoidable interstitial impurity in refractory metals and alloys, even when processing is carried out under high-purity conditions. Oxygen binds strongly to vacancies, and multiple oxygen atoms may accumulate around a single vacancy to form stable V–O<sub>n</sub> complexes. Such complexes can alter the concentration and mobility of free vacancies, introduce distinct migration mechanisms, and thereby affect vacancy-mediated diffusion and ordering kinetics in alloys. Here, we investigate the thermodynamic stability and finite-temperature mobility of V–O<sub>n</sub> complexes in refractory metals. First-principles calculations are used to determine the stability and preferred configurations of these complexes. Transition-state search methods and metadynamics are used to explore migration mechanisms and characterize the potential-energy landscapes and finite-temperature free-energy landscapes, respectively. The resulting migration mechanisms and energy barriers are used to evaluate the diffusivity of these complexes. By quantifying their mobility, this work establishes how oxygen can influence vacancy-mediated diffusion and high-temperature kinetics in refractory alloys. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Modeling and Simulation, High-Temperature Materials, Computational Materials Science & Engineering |