Phase relations, microstructure and mechanical properties of VC substituted WC-10Co cemented carbide alloys

As an effort to investigate a possible extent of substitution of W, the metal from strategic mineral, by a less strategic V, phase relations, microstructure, and hardness and fracture strength, of powder metallurgically processed 90 mass% [(1-y)WC-yVC]-10 mass% Co alloys are studied. Throughout the composition eight phases, alpha-Co, beta-Co, WC, V4C3, V8C7, eta(3)(Co3W3C), eta(6)(Co6W6C) and graphite C(g), were encountered and a distinct microstructural difference existed across midcomposition. On the basis of combined mechanical properties of hardness and fracture strength the alloys between y = 0.2 and 0.4, which correspond to 18-36 mass % VC, were most promising. Contrary to the antagonistic relations between hardness and toughness commonly encountered in cemented carbides and hard materials, the hardness and fracture strength of the present WC-VC-10Co alloys were nearly parallel. (C) 1997 Published by Elsevier Science Limited.