Microstructural and mechanical characterisation of WC–Co alloys elaborated by liquid phase sintering and hot isostatic pressing: study of WC crystallites size evolution

Abstract

ABSTRACT This work aims at the characterisation and study of WC tungsten carbide crystallites size evolution as well as of the microstructure of WC–Co alloys produced by liquid phase sintering and by hot isostatic pressing (HIP). The goal of this study is to demonstrate a possible improvement in mechanical and surface properties by using hot isostatic pressing (HIP) compared to liquid phase sintering. Two types of cemented carbides containing 11 and 20 wt-% of cobalt have been produced by two different techniques. The alloys microstructures were characterised by scanning electron microscopy (SEM). The size evolution and dimensions of WC crystallites were derived from Wagner-Halder and Williamson-Hall methods following the exploitation of X-ray diffraction line profiles. Vickers micro-hardness tests were also performed in this study. It is found that there is a clear improvement in micro-hardness for materials densified by hot isostatic pressing (HIP).