Tensile strength and fiber/matrix interfacial properties of 2D- and 3D-carbon/carbon composites

The tensile and fiber/matrix interfacial properties of 2D and 3D carbon/carbon composites (C/C) were compared. To elucidate the effect of three-dimensional reinforcement, both C/Cs were composed of the same constituents and prepared via. the same process route. The tensile fracture strain of both C/Cs degraded with increasing bulk density, and the fracture strain of the 3D-C/Cs were larger than that of the 2D-C/Cs at the same bulk density. The interfacial bonding strength of the 3D-C/Cs were found to be much lower than that of the 2D-C/Cs. From the comparison of the interfacial and tensile fracture behavior, high tensile fracture strains of 3D-C/Cs were concluded to be attributed to the weak interfacial bonding. This low interfacial strength of the 3D-C/Cs was suggested to be caused by the residual stresses induced during processing in the 3D-C/Cs due to three-dimensional restriction of the fibers.