抄録
A composite of TiB2 and TiC was synthesized from B4C and Ti powders by spark plasma sintering accompanied with the solid-state displacement reaction of them. In the early stages of the reaction, TiB, TiB2, Ti3B4, and TiC were formed as reaction. products, and finally they were changed completely into TiB2 and TiC. Relative density of composites reached more than 99 % at 1800°C and above. At 1800°C and below the composites had unique microstructure; TiB2 phases formed networks surrounding TiC phases. The network structure disappeared at higher temperatures, and TiB2 phases were dispersed more homogeneously in TiC phases. The composites obtained at 2000°C had mechanical properties of Young's modulus 514 GPa, Poisson's ratio 0.18, Vickers hardness 2090 and fracture toughness 3.8 MPa m0.5
