Abstract: In the high heat flux ablative environment, the temperature of interior and exterior of the aircraft rises rapidly, rendering traditional high thermal conductivity materials ineffective for protecting internal metal components. In this study, continuous carbon fiber reinforced low thermal conductivity Li₂O-Al₂O₃-SiO₂ (C_f/LAS) glass ceramic composites, doped with SiC particles (SiC_p), were prepared by slurry immersion winding and hot pressing sintering. The effect of matrix crystallinity on the ablative properties of the composites under ultra-high heat flux was investigated. By utilizing the heat absorption and low thermal conductivity characteristics associated with SiO₂ gasification within composite materials, both surface and internal temperatures of these materials are effectively reduced, thereby ensuring the safe operation of aircraft and electronic devices. Results indicate that the average linear ablation rate of composites doped with 10% mass fraction of SiC particles significantly decreases at a heat flux of 20 MW/m². TEM observation reveals that the doped glass matrix exhibits increased crystallinity, reduced internal stress, and minimized lattice distortion, thereby enhancing the composites’ high-temperature performance. However, excessive SiC_p doping leads to reduced crystallinity and deteriorated ablation performance. Ultimately, the average linear ablation rate of C_f/LAS composites with 10% SiC particles at 30 MW/m² heat flux is comparable to that of commercial carbon/carbon composites, while also providing lower thermal conductivity and higher bending strength. This novel high-performance C_f/LAS composite is cost-effective and suitable for mass production, offering promising potential for widespread application in hypersonic vehicles.

Key words: ablation-resistant C_f/LAS composites, SiC doping, crystallinity of glass matrix, long-range ordered