Mechanical properties and microstructures of Cf/SiC-ZrC composites using T700SC carbon fibers as reinforcements

Cf/SiC-ZrC composites were fabricated through mold-pressing and polymer infiltration and pyrolysis (PIP) process using T700SC carbon fibers as reinforcements. The effects of interphases on the mechanical properties and microstructures of composites were studied. Composite showed brittle fracture behavior and low bending stress of 81 ± 24 MPa when no interphase was deposited on the fiber surface. With the deposition of a PyC/SiC interphase, composite showed typical non-brittle fracture behavior and the bending stress increased to 401 ± 64 MPa and a large amount of pulled-out fibers could be observed on the fracture surface. Meanwhile, it could also be concluded from the microstructures of the composites that the existed interphases had a great hindering effect on the infiltration of ZrC into the intra-bundle zones in the slurry infiltration process. The TEM analysis results showed that the carbon fibers were almost not eroded and the brittle fracture behavior may be mainly ascribed to the strong bonding between fibers and matrix.