Microstructure and properties of Al2O3–TiC nanocomposites fabricated by spark plasma sintering from high-energy ball milled reactants

In situ synthesis of Al₂O₃–TiC nanocomposite powders from a mixture of titanium, graphite, and Al₂O₃ powders by high-energy ball milling (HEBM) and its consolidation through spark plasma sintering (SPS) were investigated. After being milled for 25 h at ambient temperature, the powder mixtures were mainly composed of homogeneous nanosized Al₂O₃ particle and amorphous TiC solid solution. The relative density of the samples consolidated by SPS technique in vacuum at 1480 °C for 4 min reached 99.2%. The final products exhibited very fine microstructure, and the grain sizes of Al₂O₃ and TiC were about 400 nm and 200 nm, respectively, with a flexure strength of 944 ± 21 MPa, Vickers hardness 21.0 ± 0.3 GPa, fracture toughness 3.87 ± 0.2 MPa m^1/2, and electrical conductivity 1.2787 × 10⁵ S m⁻¹.