Microstructural control of ultrafine and nanocrystalline WC-12Co-VC/Cr3C2 mixture by spark plasma sintering

The aim of this present work is to study the effect of VC and/or Cr3C2 in densification, microstructural control and mechanical behaviour of WC-12Co ultrafine and nanocrystalline mixtures, consolidated by spark plasma sintering at 1100 degrees C, applying a pressure of 80 MPa in combination with a heating rate of 100 degrees C min(-1). Nanocrystalline and ultrafine mixtures with an average size of 30 nm and 100-250 nm, respectively, with the addition of 1 and 0.5 wt.% of VC/Cr3C2 grain growth inhibitors, respectively, were investigated. The density, microstructure, hardness and fracture toughness of the consolidated samples were measured and observed. The addition of VC inhibitor allows an excellent grain growth control keeping microstructures with an average grain size of 154 nm. The hardness values and fracture toughness obtained were about 2000 HV30 and above 10 MPa m(1/2), respectively. (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.