Influence of porosity on the apparent interlaminar shear strength of pitch-based unidirectional C–C composites Original Research Article

Changes in the open porosity, bulk density and void structure through five steps of densification by coal tar pitch impregnation and recarbonization, were studied with four different unidirectional C–C composites. The changes produced in the composite microstructure were related to the apparent interlaminar shear strength and the failure behaviour of the composites. The strength increases with the number of densification steps as well as the brittle character of the failure. Relationships between microstructure and brittle behaviour of composites were investigated.