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Dense WC-x vol% cobalt (5 ≤ x ≤ 20) composites, with WC grain size of ∼1 µm, were synthesized by field-activated and pressureassisted combustion synthesis (FAPACS) within several minutes from elemental powders. Simultaneous synthesis and densification were accomplished under the combined effects of an electric field and mechanical pressure. The effect of cobalt content on the hardness, fracture toughness, and relative density of dense WC-x vol% cobalt composites was investigated. The relative density of the WC-cobalt composites increased with increased cobalt content. Under the application of a 60 MPa pressure and a 3000 A current, the final products had relatively high densities, 99.4%, for WC-20 vol% cobalt. The hardness of the WC-cobalt composites decreased with increased cobalt content, while the fracture toughness increased. The maximum fracture toughness and hardness values obtained were 9.4 MPa·m[sup ½] for the WC-20lvol % cobalt composition and 2014 kg·mm[sup -2] for the WC-5 vol% cobalt composition. [ABSTRACT FROM AUTHOR]