Effect of thermal cycling on modulus and tensile strength of 3D needled C/SiC composite in controlled environments

A needled C/SiC composite was subjected to thermal cycling with a temperature interval ranging from 700 to 1200 °C, in a pure Ar gas and a simulated air atmosphere. The change of the resonant frequencies was used to determine the reduction in the modulus of the composite. Results show that the modulus linearly decreased with increasing thermal cycles. And after thermal cycled in pure Ar and simulated air for 90 cycles, the residual tensile strengths were reduced by 46.2% and 66.5%, being caused by thermo-mismatch and combining effects of thermo-mismatch and oxidation, respectively.