Microstructure and tensile behavior of multiply needled C/SiC composite fabricated by chemical vapor infiltration

The microstructure and tensile behavior of a multiply needled C/SiC composite fabricated by chemical vapor infiltration were investigated. Results showed that the tensile stress-strain curves exhibited a typical nonlinear behavior and can be divided into three regions: a very small initial linear region followed by a large nonlinear region and finally a quasi-linear region. Needling process caused a crimp around needling fibers and reduced the bearing fibers in plane. Needling process induced damages were the main reasons for the failure of the composite. The fracture mainly occurred at the cross of needling fibers and unidirectional fibers, with the fibers showing multi-step fracture and extensive pullout. The multi-step fracture of clusters and nonlinear curves indicated a typical non-brittle failure behavior of the multiply needled C/SiC composite due to the various damage patterns.