About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Vacancy Ordering in Zirconium Carbide Explored via First-principles Calculations and Calphad |
Author(s) |
Theresa Davey, Ying Chen |
On-Site Speaker (Planned) |
Theresa Davey |
Abstract Scope |
Zirconium carbide (ZrCx) is an ultra-high temperature ceramic material with melting point around 3700 K and tuneable mechanical and thermodynamic properties thanks to its wide range of stable stoichiometry (~0.5 ≤ x ≤ 1) facilitated by varying numbers of carbon vacancies. Despite over a century of study, the low temperature equilibrium properties are relatively unknown due to high synthesis temperatures, significant impurity contamination, and slow vacancy diffusion preventing equilibration. Intermittent experimental investigations report vacancy ordering at around room temperature, which is consistent with several theoretical investigations. Short- and long-range ordering of carbon vacancies, as well as the disordered phase, was considered using first-principles calculations. The effects of temperature and oxygen impurities on vacancy ordering were examined. The results were incorporated into a Calphad database that describes the order-disorder transitions in the carbon-zirconium system, and is optimised considering all available experimental and calculated data. |
Proceedings Inclusion? |
Planned: |
Keywords |
Ceramics, Computational Materials Science & Engineering, Modeling and Simulation |