Influence of VC on the microstructure and mechanical properties of WC-Co sintered cemented carbides

The aim of this work was to evaluate the microstructural aspects and mechanical properties of a series of 90 wt% [(1 - y)WC-yVC]-10 wt% Co cemented carbides. The microstructural parameters of contiguity (C-alpha), binder mean free path (L-beta) and grain size of carbide phases (L-alpha) have been evaluated. Contiguity has a maximum value of 0.61 at the 36WC-54VC-10Co (y = 0.6) composition. The addition of V8C7 resulted in the formation of a gamma-(WxVy)C solid solution phase inhibiting the appearance of eta-(WxCoy)C grains which embrittles the body. Although the indentation fracture toughness value of 18 MPa m(1/2) obtained for y = 0.6 is acceptable, it is advisable to strictly control the predominant gamma-(WxVy)C double carbide grain size in order to achieve higher hardness values. (C) 1999 Elsevier Science Ltd. All rights reserved.