Effect of liquid phase composition on the microstructure and properties of (W,Ti)C cemented carbide cutting tools

Abstract

The microstructure and properties of (W,Ti)C cemented carbides with a different metal binder composition of Ni and Co fabricated by powder technology were investigated. The densifications of the prepared materials were accomplished by using vacuum sintering at 1450 degrees C. Nearly fully dense (W,Ti)C cemented carbides were obtained with a relative density of up to 99.7% with 30 wt% Co and 99.9% with 30 wt% Ni. The average grain size of carbides for the (W,Ti)C-Co and the (W,Ti)C-Ni was decreased with increasing the metal binder content. The hardness of the dense (W,Ti)C-15 wt%Co and (W,Ti)C-15 wt%Ni, was greater than the hardness of other different compositions of (W,Ti)C-Co and (WTi)C-Ni cemented carbides respectively; in addition, the (W,Ti)C-Co cemented carbides had greater hardness values than the (W,Ti)C-Ni cemented carbides. The magnetic properties, which were measured at an applied field of 0.8 T, indicate that the (W,Ti)C-Co cemented carbides have ferromagnetic properties with a higher magnetic saturation with higher cobalt content as well as higher coercivity with lower cobalt content. On the other hand, the (W,Ti)C-Ni cemented carbides are non-magnetic on account of the very low magnetic saturation and they have lower coercivity values than the (W,Ti)C-Co cemented carbides. (C) 2008 Elsevier Ltd. All rights reserved.