Research on continuous fiber reinforced silicon carbide composites

Silicon carbide textile composites reinforced with continuous carbon and silicon carbide fiber were fabricated by chemical vapor infiltration. The densities of C/SiC composites and SiC/SiC composites after the 30 h infiltration are 2.1 g·cm^-3 and 2.5 g·cm^-3 respectively. The flexural strength values of C/SiC composites and SiC/SiC composites are 450 MPa and 860 MPa respectively, which are not reduced as the temperature is increased from room temperature to 1600°C. Accordingly, the fracture toughness values are 20 MPa·m^1/2 and 41.5 MPa·m^1/2, the fracture work values are 10 kJ·m^-2 and 28.1 kJ·m^-2, and the dynamic impact fracture toughness values are 62.0 kJ·m^-2 and 36.0 kJ·m^-2, respectively. After thermal shock tests between 300°C and 1300°C for 50 times, the flexural strength is retained by 96.4%. It is indicated that the thermal shock is not a controlling factor for the failure of C/SiC and SiC/SiC materials. Compared with C/SiC composites, SiC/SiC composites exhibit superior oxidation resistance. Especially, both C/SiC and SiC/SiC thruster chambers have successfully passed the test of rocket engine.