Microstructure and mechanical properties of carbon fibre-reinforced alumina composites fabricated from sol

[摘要] Alumina matrix composites reinforced with the laminated and stitched carbon fibre cloth preform were fabricated through the infiltration–drying–heating route using the Al$_2$O$_3$ sol with a high solid content as raw materials. The investigation was focussed on the characteristics of sol and the mechanical properties and high-temperature resistance of C/Al$_2$O$_3$ composites. $\alpha$-Al$_2$O$_3$ with favourable sintering activity can be obtained after heat treatment of sol at 1200$^{\circ}$C. The as received C/Al$_2$O$_3$composites with a total porosity of 16.8% exhibit a flexural strength of 271.3 MPa and a notch toughness of 13.0 MPa m$^{1/2}$, respectively. As a result of the evolution of interface and matrix, the flexural strength of C/Al$_2$O$_3$composites is decreased by 28.5% after heat treatment at 1600$^{\circ}$C for 1 h under inert atmosphere. At the same time, fracture mode of composites is transformed from tough to brittle behaviour.

[学科分类] 材料工程

[关键词] Alumina;composites;carbon fibre reinforcement;sol;mechanical properties.