Microstructure and flexural properties of C/SiC composites by CVI-RMI method

Pyrolytic carbon coating and successive SiC matrix were respectively prepared by chemical vapor infiltration (CVI) in T700 kind integer felt. The subsequent reactive melt infiltration (RMI) method was adopted to dcnsify it further and C/SiC composites were successively prepared. The microstructure and effect of interface on flexural properties were thoroughly investigated. The results show that C/SiC composites fabricated by CVI-RMI methods have high density and low porosity(10%), in which CVI-SiC and RMI-SiC distribute uniformly. The flexural strength of the composites is 133 MPa. The composites are damaged layer by layer with good pseudo-plasticity. C fibers are damaged lightly because of pyrolytic carbon coating and CVI-SiC. Pyrolytic carbon coating moderates the interface strength between C fibers and SiC, which is beneficial to the pulling out of C fibers.