Microstructure and mechanical properties of TiB₂-40 wt% TiC composites: Effects of adding a low-temperature hold prior to sintering at high temperatures

TiB₂–40 wt% TiC composites were prepared by pressureless sintering. Prior to the conventional heating at 2000 °C for 1 h for final densification, addition of a low temperature hold at 1500 °C for 4 h was found effective in densification of the composite, refining the microstructure and promoting the anisotropic growth of TiB₂ grains. The TiB₂-TiC composite prepared by two-step sintering had better mechanical properties with flexural strength of 776 MPa and fracture toughness of 7.43 MPa m^1/2, in comparison with the values of 419 MPa and 4.81 MPa m^1/2 for composite by conventional one-step sintering.