With titanium and hexagonal boron nitride powders as raw materials, TiN-TiB₂ composites were fabricated via spark plasma sintering (SPS), and the effects of sintering holding time on the microstructure and mechanical properties of the composites were investigated. The results indicate that at a sintering temperature of 1 600 ℃, with pressure of 50 MPa and holding time ranging from 10 min to 20 min, the prepared TiN-TiB₂ composites consist of TiN and TiB₂ phases. As holding time increases from 10 min to 20 min, the interfacial bonding between phases is strengthened and atomic diffusion becomes more sufficient. Consequently, grains grow gradually and exhibit a more regular morphology. The mechanical properties of the composite firstly increase and then decrease with prolonged holding time, closely correlated to grain growth. With holding time of 15 min, the composite presents optimal mechanical properties: its hardness, flexural strength and fracture toughness reach (21.5±0.18) GPa, (618±18) MPa and (5.45±0.07) MPa·m^1/2, respectively.

spark plasma sintering (SPS)  /  TiN  /  TiB₂  /  in-situ synthesis  /  ceramic material  /  composite materials  /  microstructure  /  mechanical property