| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Simulations/Experiments Integration for Next Generation Hypersonic Materials
|
| Presentation Title |
First-principles Calculations of Diffusion Coefficients in High-temperature Carbides |
| Author(s) |
Indiras Khatri, Raj Koju, Yuri Mishin |
| On-Site Speaker (Planned) |
Indiras Khatri |
| Abstract Scope |
We present a new methodology for first-principles calculations of point defects and diffusion in ultra-high temperature transition-metal carbides with the B1 (rock salt) structure, such as TaC and HfC. These carbides are potential candidates for hypersonic applications. The formation and binding energies of point defects and their clusters are calculated and used as input into a statistical model to predict equilibrium point-defect concentrations as a function of temperature and chemical composition. Jump barriers of point defects are computed and combined with kinetic models to predict diffusion coefficients of the metallic and carbon atoms by several mechanisms. The jump correlation factors required for the calculations are obtained by kinetic Monte Carlo simulations. In addition to self-diffusion, impurity diffusion coefficients of Hf atoms in TaC and Ta atoms in HfC are computed within a 5-frequency model. Possible extensions of the methodology to interdiffusion are discussed. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Ceramics, Modeling and Simulation, Computational Materials Science & Engineering |