PUSH-OUT TESTS ON A NEW SILICON-CARBIDE REACTION-BONDED SILICON-CARBIDE CERAMIC-MATRIX COMPOSITE

Fiber push-out tests have been performed on a ceramic matrix composite consisting of Carborundum sintered SiC fibers, with a BN coating, embedded in a reaction-bonded SiC matrix. Analysis of the push-out data, utilizing the most complete theory presently available, shows that one of the fiber/coating/matrix interfaces has a low fracture energy (one-tenth that of the fiber) and a moderate sliding resistance tau almost-equal-to 8 MPa. The debonded sliding interface shows some continuous but minor abrasion, which appears to increase the sliding resistance, but overall the system exhibits very clean smooth sliding. The tensile response of a full-scale composite is then modeled, using data obtained here and known fiber strengths, to demonstrate the good composite behavior predicted for this material.