| Abstract Scope |
Ultra-high temperature ceramics (UHTCs) and composites (UHTCMCs) are candidate materials for demanding aerospace applications. In this talk, we will present the latest developments of the revised physics-based model for oxidation of MeB2-SiC UHTCs in oxygen, water vapor, and oxygen-water vapor mixtures that we proposed recently. First, the expanded physics of the revised model required additional parameters, such as permeability of water, hydrogen, and CO(g) in SiO₂ and B₂O₃, as well as the coefficient of interdiffusion in borosilicate glass. Interdiffusion in the glass portion of the oxide scale was identified as one of the key processes that control the oxidation rate and the mode of oxidation. The available data from the literature will be presented, along with a thermodynamic model that describes the non-ideal behavior of interdiffusion coefficient and viscosity of borosilicate glass as a function of temperature and composition. Second, the extension of the present model to the ultra-high temperature ceramic matrix composites will be discussed and illustrated. Last, we will present and discuss our overall vision for future integrated aero-thermo-mechanical modeling of environmental response of UHTCs and UHTCMCs. |