| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Simulations/Experiments Integration for Next Generation Hypersonic Materials
|
| Presentation Title |
High-temperature Oxygen Plasma Experiments and Atomistic Simulations of Active Oxidation in Nanocrystalline SiC Woven Fibers |
| Author(s) |
Frederic Sansoz, Luc Capaldi |
| On-Site Speaker (Planned) |
Frederic Sansoz |
| Abstract Scope |
High-temperature oxidation of nanocrystalline SiC fibers is critical for the deployment of advanced flexible thermal protection systems such as hypersonic inflatable aerodynamic decelerators. Experimental evidence shows that woven SiC ceramic fibers are prone to accelerated fiber embrittlement under high-temperature oxidation in dynamic oxygen environments. The nanocrystalline structure of the constituent fibers impacts the reaction kinetics and phase transformations during active oxidation. This talk will present large-scale molecular dynamics simulations with a reactive force-field, supported by direct observations from high-enthalpy oxygen plasma experiments, to elucidate the complex roles of grain boundaries on oxidation kinetics and the nature of oxides produced in both monocrystalline and nanocrystalline 3C-SiC between 1100K and 2000K. We find that nanocrystalline SiC exhibits two distinct oxidation kinetics with a transition at 1500K due to the formation of a liquid Si phase at the SiC/Si oxide interface. Incoherent grain boundaries promote the stability of this interfacial liquid phase. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Ceramics, High-Temperature Materials, Phase Transformations |