Failure behavior of interfacial domain in SiC-matrix based composites

In this work, the microstructure, failure behavior and interfacial properties with respective to the interfacial domain in SiC_f/BN/SiC and C_f/PyC/SiC composites were studied via the fiber push-in test. The differences in the mechanical response of the interfacial domain were observed. During the fiber push-in test for SiC_f/BN/SiC, the interface debonding accompanied with interphase fracture occurred, resulting in an obvious sign of the onset of debonding on loading-displacement (P-u) curves. While the good continuity of P-u curves can be observed for C_f/PyC/SiC, which is due to that the failure is in the form of interface debonding along with interphase lateral slipping caused by the extension of buckled carbon fiber, without any interphase fracture. The interfacial properties calculated from the fiber push-in test show that C_f/PyC/SiC possesses a weaker interfacial domain compared with SiC_f/BN/SiC. The interfacial shear stress of SiC_f/BN/SiC and C_f/PyC/SiC composites amounts 94.2 and 48.1 MPa, respectively.