Mechanical properties of SiC/SiC composites by PIP process with a new precursor at elevated temperature

Three dimensional (3D) braided silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC composites) were fabricated by precursor impregnation and pyrolysis (PIP) process with a new precursor. Liquid polyvinylcarbosilane (LPVCS) with active SiH and –CHCH2 groups was adopted as the SiC matrix precursor. The SiC/SiC composites with superior density and high-temperature mechanical properties were efficiently fabricated. Bulk density and porosity of the composites were 2.16 g/cm3 and 10.4% respectively. At 1300 °C, the flexural strength and the fracture toughness were 470.2 MPa and 20.7 MPa m1/2, and the tensile strength and the Young׳s modulus were 226.4 MPa and 34.1 GPa respectively. Performance degradation of the SiC fibers and the consumption of the PyC interface by oxidation at 1300 °C illuminated the damage mechanisms of SiC/SiC composites.