Synthesis mechanism and mechanical properties of TiB2–SiC composites fabricated with the B4C–TiC–Si system by reactive hot pressing

High-performance TiB 2 –SiC composites were fabricated with a new reaction system of B 4 C–TiC–Si by reactive hot pressing. The reaction process was controlled by the diffusion of boron atoms and hindered by the accumulated product layer of TiB 2 and C. The melting Si can offer another diffusion path for boron atoms, thereby promoting the reaction process. The Vickers hardness , flexural strength , and fracture toughness of the fabricated TiB 2 –SiC composites respectively reached 28.6   ±   0.6   GPa, 654   ±   49   MPa, and 6.8   ±   0.5   MPa   m 1/2 . Both the intergranular fracture resulting from mismatch in thermal expansion coefficient between TiB 2 and SiC and the transgranular fracture resulting from the network structure of TiB 2 can enhance the fracture toughness of the TiB 2 –SiC composite.