Effect of interface structures on the fracture behavior of two-dimensional carbon/carbon composites by isothermal chemical vapor infiltration

The interface structures and fracture behavior of the two-dimensional carbon/carbon composites by isothermal vapor infiltration have been investigated. The results show that the graphene layers exhibit long-range order in high/textured pyrocarbon matrix and are curved in about 5-nm interface region of the fiber/high-textured. Some globular nanoparticles are formed on the fiber surface and the high-textured layer about 10 nm exists in the interface of the fiber/low-textured. The graphene layers stacks are scrolled and folded in the medium-textured and they are waved together in the interface of the fiber/medium-textured. The pseudo-plastic fracture behavior of the two-dimensional carbon/carbon composites is resulted from the dominant high-textured matrix and a moderate interfacial bonding force. A strong adhesion of the fiber/low-textured and the thicker fiber increased by surrounding low-textured layer result in the increasing flexural strength. The single medium-textured and a very strong bonding force of the fiber/medium-textured lead to the brittle fracture behavior.