Fabrication and flexural properties of Tyranno-SA/SiC composites with carbon interlayer by CVI

Strength reliability and thermal stability of SiC/SiC composites are important as structural candidates for nuclear fusion reactor. Several CVI-Tyranno-SA (plain-woven)/SiC composites were fabricated and the flexural strength and the effects of the high temperature heat treatment in vacuum were investigated. The flexural strength and statistical properties of the as-fabricated composites showed a dependence on composite density. The highest average strength, 640 ± 69 MPa, with the highest Weibull modulus, m=12.2, was obtained by the composite with the highest density among the several composites. No significant change of the strength of the composite was noticed against heat treatment at temperature up to 1973 K in vacuum of ∼3 × 10−4 Pa for 1 h, beyond which the strength decreased with the increasing of the heat treatment temperature.