Effect of porosity content on composition of W/ZrC composites produced by displacive compensation of porosity (DCP) method

Abstract

Tungsten based composites such as W/Cu have successfully been used in high temperature environments. In order to reduce the weight and improve their erosion resistance, W/ZrC composite has already been developed via displacive compensation of porosity method by Dickerson et al. The aim of this work was to investigate the effect of preform porosity on the composition of final composite. For this purpose, a mixture of tungsten carbide powder and PVA was cold isostatic pressed to make a porous tungsten carbide preform. The porous perform was debinded for 14·4×10³ s at 673 K and sintered for 14·4×10³ s at 1673 K. The sintered perform was then infiltrated by molten Zr₂Cu at 1573 K for 25·2×10³ s. The cross-section of infiltrated specimens was studied using scanning electron microscopy equipped with an energy dispersive spectroscope analyser as well as X-ray diffraction. The results indicated that the amount of tungsten and zirconium carbide phases in final composite increased as the porosity of WC preform increased. The relative density of W/ZrC composite reduced with increasing initial porosity of sintered preform.