Effects of heat treatment temperatures on microstructures and mechanical properties of the chopped carbon fibres SiC composites

A simple wet papermaking technique was used to fabricate chopped carbon fibre paper (C_sf-paper) with random fibre orientation and self-supporting network structures in this work. The C_sf-papers were laminated layer by layer and further infiltrated with PyC interface and SiC matrix via chemical vapour infiltration (CVI) to obtain C_sf/SiC composites. The effects of heat treatment temperatures on microstructures, phase composition, and mechanical properties were investigated. Results showed that the C_sf-paper has played a good self-supporting role and its fibres form a completely random fibre orientation in 2D plane. The fibres almost remained undamaged and unbroken during the CVI. Proper heat treatment could improve the mechanical properties. At 1200°C, the maximum values of flexural strength and Young's modulus reached about 306 MPa and 196.5 GPa, respectively. Meanwhile, compared with tape casting, reaction sintering and spark plasma sintering, composites fabricated by wet papermaking and CVI can improve the mechanical properties.