Microstructure and Properties of Al_2O_3-TiC Composites Fabricated by Combination of High-energy Ball Milling and Spark Plasma Sintering (SPS)

Aluminothermic reactive synthesis of Al2O3-TiC nanocomposite powders from a mixture of TiO2, Al, and C powders induced by high-energy ball milling and its consolidation through spark plasma sintering (SPS) were investigated. After being milled for 3h at ambient temperature, the powder mixtures reacted and homogeneous nanosized TiC and Al2O3 particles formed. The as-milled powders were consolidated by SPS technique in vacuum at 1450℃ for 4min under 50MPa, and the density of the as-sintered samples reached 99.6% of theoretical density. The final products showed fine microstructure, and most of the grain sizes of both Al2O3 and TiC were less than 1μm, and exhibited excellent properties: a flexural strength of 650±21MPa, a hardness of 19.1±0.2GPa, a fracture toughness of 4.5±0.2MPa·m1/2, and an electrical conductivity of 2.3828×105Ω-1·m-1.