Influence of fiber/matrix interface on the texture evolution and fracture toughness of C/C

Abstract

This study was conducted to obtain a more in-depth insight into the role of fiber/matrix interface on the texture and mechanical performance of carbon fiber reinforced carbon composites (C/C). In this study, a series of isothermal chemical vapor infiltration (ICVI) experiments were performed on the deposition of pyrocarbon (PyC) onto carbon fibers (CFs) and pre-oxidized fibers (PFs). The results showed that the graphitization degree and orientation angle (OA) of the fiber and matrix of the PF-SL were relatively low compared with the CF-SL. Most importantly, the OA of CF-SL between the interfaces was much higher than that of PF-SL. Besides, a low texture transition layer with a width of tens of nanometers was observed between the fiber/matrix interfaces, which may reduce the lattice distortion and interfacial energy. In addition, the fracture toughness of CF-SL was higher than that of PF-SL, which was attributed to interfacial differences. Further, PF-SL had a coarser interface than CF-SL due to the carbonization reaction during ICVI, which induced gas escape and PF shrinkage and bulges on the surface.