Model single point abrasion experiments on WC/Co hardmetals

Abstract WC based hardmetals are widely used in applications where abrasion resistance is important. This paper describes the utility of scratch tests as model single point abrasion tests to evaluate the response of WC/Co hardmetals to the type of conditions that will occur in abrasion. The different types of experiments were single and multiple pass tests, and multiple pass tests in corrosive media. The resultant scratches were observed by stepwise SEM imaging, stereographic image correlation and 3D reconstruction, and EBSD analysis. It was found that many of the features observed in the model tests paralleled those seen in other abrasive tests on WC/Co materials such as build up of plastic damage in WC grains, fracture and fragmentation of WC grains, deformation of the Co binder phase and re-embedment of WC grains in the surface layers of the material. For tests in the presence of corrosive media, the binder phase was removed early in the sequence of scratches, leading to breakdown of the structure of the material. Stereo reconstruction was shown to be a valuable way of visualising and measuring the physical dimensions of scratches, providing a future route for the quantification of damage in these model experiments.