Improvement of the mechanical properties of two-dimensional carbon/carbon composites

The microstructure of carbon matrix was modified and the interfaces between filler/matrix and fiber/matrix were improved by the fillers including expanded graphite and vapor-grown spiral carbon fiber (VGSCF), used as a secondary reinforcement in the carbon matrix. The optimized two-dimensional carbon/carbon composites (C/Cs) were fabricated by adjusting the mass ratio of the two fillers, 5 wt.% expanded graphite and 7 wt.% VGSCF. The flexural strength, flexural modulus and fracture strain of the 2D C/Cs amount to 130.6 MPa, 20.26 GPa and 1.86%, respectively. The fracture mode of the 2D C/Cs exhibits a pseudo-plastic behavior. A secondary reinforcement model is proposed to explain the propagation of microcracks and the mechanism of toughness improvement in 2D C/Cs.