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Nano-sized Co and Al_2O_3 powders were successfully synthesized from 3/4Co_3O_4 and 2Al by highenergy ball milling. A dense nanocrystalline 2.25Co-Al_2O_3 composite was consolidated from mechanically synthesized powders by the pulsed current activated sintering (PCAS) method within 2 min. Consolidation was accomplished under the combined effects of a pulsed current and mechanical pressure. A dense 2.25Co-Al_2O_3 with relative density of up to 95% was produced under simultaneous application of a 80 MPa pressure and a pulsed current of 2800 A. The fracture toughness and hardness of the 2.25Co-Al_2O_3 composite were 8 MPa · m^1/2, 870 kg/㎟, respectively.