Microstructure and mechanical properties of 3D needled carbon fibre reinforced carbon and silicon carbide composites

摘要

Three-dimensional needle carbon fibre reinforced carbon and silicon carbide dual matrix composite (C/C-SiC) was a new type of high performance brake materials, and exhibited a series of outstanding advantages such as low density, good echanical properties, especially excellent toughness, to avoid catastrophic brittle fracture. In the present study, the C/C-SiC composites were fabricated by the combination of chemical vapor infiltration with liquid silicon infiltration. The preform was prepared by three dimension needling method. The preform was densified by chemical vapor infiltration to form porous carbon/carbon (C/C) composites. Then, the porous C/C composites were converted into C/C-SiC during LSI, in which silicon carbide matrix was formed by the reaction of carbon and melt silicon. The microstructure and mechanical properties of C/C-SiC has been investigated. The results indicated that the composites were composed of 55 wt%C, 39 wt%SiC and 6 wt%Si. The density of C/C-SiC was 2.2 g·cm~(-3) and the open porosity was 6.4%, respectively. The C/C-SiC exhibited good echanical properties, especially excellent toughness, to avoid catastrophic brittle fracture. The flexural and compressive strength can reach to 214.6 MPa and 271.0 MPa, respectively. C/C-SiC had excellent impact damage tolerance of 25.2 kJ·m~(-2).