Strength evaluation after environmental exposure and fabrication of trial parts in SiC/SiC ceramic matrix composite for space re-entry vehicles

Ceramic matrix composite (CMC), made by a processing technique using a polymer impregnation and pyrolysis method, was evaluated environmentally under thermal exposure. After thermal exposure simulating practical use in the future space vehicles, the material possessed approximately 80 to 90% of the strength at ambient temperature and showed no reduction in strength at a high temperature of 1673 K. Trial parts using the present CMC material were fabricated successfully to the shape of a TPS flat panel and a leading edge curved panel. Although the density of the trial parts increased with increasing densification cycle and slightly smaller than a flat panel, the integrity was confirmed by an ultrasonic NDI method. Furthermore, the trial parts had sufficient strength as a structural component and the strength and fracture morphology were predicted reasonably by a FEM analysis using the material data resulted from coupon size specimens. Therefore, it was concluded that the CMC material had potential as candidate of structural heat resistant material for space re-entry vehicles.