Phase control of WC–Co hardmetal using additive manufacturing technologies

Abstract

Three-dimensional WC–Co hardmetal samples were fabricated using WC–Co nanopowder via two methods: selective laser melting (SLM) and fused deposition modelling (FDM). The carbon loss and phase transition during processing were controlled to minimise the degradation of mechanical properties of the cemented carbide. The SLM samples were manufactured from granule powder produced via spray drying, whereas the FDM process was carried out on a filament produced via injection moulding. During SLM, carbon loss occurred due to the high energy involved in the process. Owing to carbon loss, the relative density and Rockwell hardness of SLM processed samples were low. To overcome this, a stable WC phase cemented carbide was manufactured via FDM. The density of the sintered FDM samples was improved by increasing the packing density of the filaments. The carbide sintered samples had a relative density of 96.3%, hardness of HRA 89.06 and carbon content of 5.47–5.52 wt-%.