Optimization of the Thermal Shock Resistance of Carbon-Carbon Composites
SourceA three-dimensional rule of mixtures model was developed to calculate the room-temperature thermal and mechanical properties of carbon-carbon composites whose constituents have anisotropic properties. The model was used, along with the properties of different carbon fibers and pyrocarbon matrices, to determine the fiber-matrix combination, constituent volume fractions, and constituent orientations that maximize expected composite thermal shock resistance of heat shields. The results indicate that a composite having a low volume fraction of high-modulus carbon fibers, arranged in a 3D array, and coated with anisotropic, heat-treated pyrocarbon matrix, will have the maximum thermal shock resistance. Confidence in the model was established by good agreement between model predictions and experimental data on actual carbon-carbon composites.