A Mortise–tenon Joint Inspired Interface Structure Design for Synergistically Enhancing the Mechanical Properties and Thermal Shock Resistance of Cf/(HfNbTaTiZr)C–SiC Composites

Carbon fiber-reinforced high-entropy carbide ceramics (Cf/HECs) are considered promising candidates for ultrahigh-temperature structural applications. The fiber-matrix interface plays a crucial role in determining the overall performance of these materials. This study proposes a novel interface design strategy inspired by the traditional Chinese mortise-tenon joint. In this design, microscale carbon spheres are deposited on the surface of carbon fibers to function as the "tenon", while the matrix serves as the corresponding "mortise". Furthermore, a TiC interfacial layer is introduced to improve the interfacial bonding through atomic diffusion. Owing to this distinctive interface structure, the resulting Cf/(TiZrHfNbTa)C-SiC composite exhibits excellent mechanical properties, with a flexural strength of 1053.33 MPa and a fracture toughness of 9.77 MPa & centerdot;m1/2. Additionally, the composite demonstrates remarkable thermal shock resistance, with a critical thermal shock temperature difference (Delta Tc) of 802 degrees C. It also displays superior ablation resistance, characterized by a linear ablation rate of 3.27 mu m & centerdot;s-1 and a mass ablation rate of 0.05 mg & centerdot;s-1.