High temperature tensile properties of near-stoichiometric SiC fiber-reinforced SiC matrix composites

SiC/SiC composites reinforced with near-stoichiometric SiC fiber, Tyranno™SA, were fabricated by forced-flow chemical vapor infiltration method and their tensile properties were evaluated at room temperature in air and at elevated temperature under mild oxidizing gases atmosphere. Tensile strength was nearly independent of porosity. Higher Proportional Limit Stress was obtained with smaller porosity. Tensile strength of composite was slightly decreased at 1573 K, while it retained approximately 80% of the strength at room temperature. The decrease of fiber-matrix interfacial sliding stress might be the reason for the reduction of tensile strength.