Residual mechanical properties of bio-inspired carbon-based composites with multilayer toughened shell-pearl structure

• The C/(PyC/SiC) n composites with biomimetic pearl shell layers were prepared adopting one-step CVI method . • The C/(PyC/SiC) 5 composites possess the characteristics of high specific strength and residual flexural strength . • The cracks initiate and deflect at multi-layer interface due to the higher clamping stress to improve the flexural strength. Shells are natural composites with outstanding mechanical properties, achieved through a combination of calcium carbonate flakes and organic layers arrangements. Here, inspired by the layered structure of shell pearl, we report a C f /(PyC/SiC) n composites with high residual strength and good anti-ablation properties prepared via one-step chemical vapor infiltration method. The layered biomimetic structure increased the sliding resistance induced by the clamping stress to promote cracks deflection at multi-layer interface, where multiple crack initiation at a PyC weak layer followed by crack deflection in a SiC tough layer. The flexural strength of as-prepared C f /(PyC/SiC) 5 composite was significantly improved about 55.7 % in comparation to C f /PyC/SiC composite. After ablation, the flexural strength of C f /(PyC/SiC) 5 composite degraded by only 11.2 %, while that of C f /PyC/SiC composite reduced about 32.4 %. This work is expected to provide insights for the preparation of high-performance carbon-based composites, with promising applications as thermal protection materials in aerodynamic heating environments.