A ceramization strategy of alumina fiber reinforced composites modified with TiCN and B4C: Enhanced mechanical robustness, ablation resistance and thermal insulation

Alumina fiber reinforced composites (AFC) have attracted massive attention in thermal protection materials due to their excellent high temperature mechanical properties. However, the application of the AFCs is restricted by their easy failure at high temperature condition for the sake of phase transition and grain growth. In this work, a series of alumina fiber based ceramizable composites modified with TiCN and B 4 C were prepared. The thermal stability, phase evolution, thermal insulation performance and anti-ablation mechanism of the composites were investigated. The flexural strength and residual weight yield of obtained ceramizable composite after static ablation at 1200 ℃ was 22.3 MPa and 85.8 %, showing obvious enhancement compared with those of the composite without ceramic fillers. The good ablation resistance and high temperature bearing capacity of the composites can be attributed to the formation of protective layer of rutile phase TiO 2 and the grain-refining effect of ceramic phase.