In-situ high-temperature mechanical performance and oxidation resistance mechanism of Ti3SiC2 modified carbon fiber/boron phenolic resin ceramizable composite

Carbon fiber/phenolic resin composite (CF/Ph) is widely used for the large-area thermal protection of hypersonic vehicles due to its excellent processing characteristics and performance advantages. As the thermal protection material, CF/Ph must possess outstanding ablation resistance and robust load-bearing capacity to ensure the structural integrity and shape stability of hypersonic vehicles. However, so far, research on the in-situ high-temperature mechanical performance and oxidation resistance mechanism of the CF/Ph is lacking. In this study, the high-temperature mechanical performance of Ti 3 SiC 2 modified carbon fiber/boron phenolic resin ceramizable composite (Ti 3 SiC 2 -CF/BPRC) was evaluated using in-situ high-temperature bending test. High-temperature microscopy and in-situ X-ray diffraction were used to obtain the in-situ micromorphology evolution and phase composition at high temperatures. The combination of in-situ characterizations and ex-situ characterizations (microstructure and phase analysis after high-temperature testing) elucidated the in-situ oxidation resistance mechanism of Ti 3 SiC 2 -CF/BPRC. The results demonstrate that Ti 3 SiC 2 -CF/BPRC exhibits excellent oxidation resistance and high-temperature bending performance, with a residual yield of 29.2% at 1300 °C and a bending strength of 25.1 MPa at 1200 °C, attributed to the oxygen consumption, oxygen diffusion inhibition, carbon fixation, and endothermic reactions of Ti 3 SiC 2 , along with the formation of a Ti-B-O-C-Si multiphase ceramic layer. This work provides critical insights into the in-situ high-temperature oxidation mechanisms of ceramizable composite.