Effect of intermediate heat treatment on the fabrication and mechanical properties of thin wall C/C SiC components

Thin wall C/C-SiC components were fabricated by "chemical vapor infiltration + precursor impregnation pyrolysis" (CVI+PIP) combined methods. The effects of intermediate heat-treated C/C porous preform on the density, deformation and mechanical properties of C/C-SiC components were investigated. The results show that the intermediate heat treatment of the C/C porous preform results in carbon with open porosity, which is favorable for SiC infiltration, leading to the preparation of a C/C-SiC component with high density. The interlaminar shear properties are not influenced observably by intermediate heat treatment, while the in-plane tensile strength and integral bearing performance are affected. The thin wall C/C-SiC components deform on the inside and outside diameter and height orientation by intermediate heat treatment. The in-plane tensile strength and integral bearing performance of the components with proper interfacial strength increase obviously after heat treatment at appropriate temperature (1600-1800℃), and the higher temperature treatment (2100-2300℃) reduces the strength of carbon fiber and reduces the tensile strength and integral bearing performance of C/C-SiC components evidently.