中國(guó)有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 28 No. 11 November 2018 |
（1. School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China;
2. Science and Technology on Advanced Ceramic Fibers & Composites Laboratory, National University of Defense Technology, Changsha 410073, China）
Abstract:To prepare the three-dimensional braided carbon fiber reinforced mullite (3D C/mullite) composites, an Al2O3-SiO2 sol with a solid content of 20% (mass fraction) and an Al2O3/SiO2 mass ratio of 2:1 was selected as the raw material. Characteristics and mullitization of the sol were analyzed throughly. It is found that the formation of mullite is basically completed at 1300 °C and the gel powders exhibit favorable sintering shrinkage. The 3D C/mullite composites without interfacial coating were fabricated through the route of vacuum impregnation-drying-heat treatment. Satisfied mechanical properties with a flexural strength of 241.2 MPa and a fracture toughness of 10.9 MPa？m1/2 are obtained although the total porosity reaches 26.0%. Oxidation resistances of the composites at 1200, 1400 and 1600 °C were investigated. Due to the further densification of matrix, the 3D C/mullite composites show tiny mass loss and their mechanical properties are well retained after oxidation at 1600 °C for 30 min.
Key words: carbon fiber reinforced mullite composites; Al2O3-SiO2 sol; mechanical properties; oxidation resistance
