Effects of scale combination and contact condition of raw powders on SPS sintered near-nanocrystalline WC-Co alloy

The near-nanocrystalline WC-10Co alloys were prepared by spark plasma sintering (SPS) using sub-micron WC/nano-Co and sub-micron WC/micron Co as the raw powders. The SPS process, the microstructures and properties of the sintered WC-Co bulks were investigated systematically. Compared with the bulk prepared using the sub-micron WC/nano-Co mixed powders, the sintered bulk with the sub-micron WC/micron Co as raw powders and a pre-treatment of ball-milling has a high density, and hardness of HRA94.5 and fracture toughness of 13.50 MPa m(1/2), respectively, indicating an excellent combination of mechanical properties. The densification mechanisms of SPS sintered near-nanocrystalline WC-Co alloys have been analyzed, and for the first time the effects of scale combination and contact condition of WC/Co raw powders on the microstructure and properties of the bulk have been proposed. (C) 2007 Elsevier B.V. All rights reserved.