Abstract: TiB_2-xwt%CNT_s-5wt%Ni (x=0.1, 0.3, 0.5, 1, 4) composites reinforced by carbon nanotube were fabricated by hot-pressing sintering and the prepared conditions, mechanical properties and microstructure were also investigated. XRD and SEM were used to analyze the phase and fracture surface. The results show that the hardness, bending strength and fracture toughness of the composite reinforced by carbon nanotube are increased distinctly. When the carbon nanotube content is 0.5wt%, the bending strength attains 496MPa; moreover the value of hardness and fracture toughness reaches 20.5GPa and 7.25MPa·m^1/2 respectively. The
analysis of fracture photograph reveals that the carbon nanotube mainly distributes at the TiB2 grain boundary. The main toughing mechanisms of the TiB₂-CNTs-Ni composite are CNTs pulled-out and CNTs bridging.

Key words: carbon nanotube, TiB2 ceramic matrix composite, mechanical properties, microstructure