Influence of microstructure on modal work-of-fracture of carbon fibre/pitch-derived carbon composites

Influence of microstructure on multi-modal work-of-fracture of carbon fibre/pitch-derived carbon composites (C/C composites) was studied. C/C composites in which matrix textures were flow type and mosaic type were prepared. Besides, C/C composites were heat-treated at 1000°C-2800°C. Modal work-of-fractures of tensile fracture and interlaminar shear fractures of the composites were simultaneously estimated. The modal work-of-fracture of tensile fracture was governed by the energy dissipation in fibre pullout process. The energy dissipation in fibre pull-out process was changed by the volume fraction of fibre, texture of matrix carbon and development of graphite crystallite. On the other hand, the modal work-of-fracture of interlaminar shear fracture was explained by debris density on the interlaminar shear fracture surface.