Modeling of Simultaneous Oxidation and Volatilization Phenomena Along a Crack in a Self-Healing Multi-constituent Material

Abstract

Multilayer ceramic matrix composites with self-healing capacities have been developed for high-temperature aeronautical applications. However, the use of these sophisticated materials leads to complex thermo-chemical behavior which requires a proper analysis. Previous models have allowed to determine the quantity of oxygen reaching the fiber at the end of a crack, in a dry atmosphere. The focus of this study was to extend this model to the case of humid atmospheres, for the presence of moisture can lead to the volatilization of the healing oxide. Applications of the model were conducted on a material composed of successive layers of SiC and B4C. Changes of the crack wall surface could then be evaluated, as well as the healing or recession behavior, and the evolution of the oxygen concentration. Moreover, the introduction of a uniform equivalent averaged material allowed estimations of the consumption of all constituents, and in particular of carbon interphase, over durations representative of aeronautical service lives.