In-situ bending behavior and failure characterization of 3D needle-punched C/SiC composites

In-situ failure characterization of three-dimensional (3D) needle-punched C/SiC composites under three-point bending test were experimentally investigated. The non-linear macroscopic load-displacement curve was obtained. The evolution of displacement and strain fields during loading were reproduced by stereo-digital image correlation (stereo-DIC). The macro-damage and fractured surface after the three-point bending test was investigated by using an optical microscopy and scanning electron microscopy (SEM). The results show that the 3D needle-punched C/SiC composites have a flexural strength of 222.9 MPa with a typical non-brittle failure behavior. The failure mechanisms include the fibers and fiber bundles pull-out, the PyC/fiber interfacial debonding, fiber fracture and the matrix cracking.