Laser-Based Additive Manufacturing of WC-Co with High-Temperature Powder Bed Preheating

The field of additive manufacturing (AM), and especially laser powder-bed fusion (LPBF), is constantly growing. Process windows for a large variety of materials are already developed. Nevertheless, some materials are still difficult to manufacture with LPBF. One of these materials is the tungsten carbide/cobalt-based hard metal (WC-Co), which is conventionally produced by powder metallurgy including liquid-phase sintering. Most approaches to manufacture WC-Co with LPBF show a high porosity, undesirable phases in the microstructure, and inhomogeneous carbide distribution. However, the production of WC-Co cutting tools by LPBF will offer some benefits such as production of geometrically optimized inner cooling channels or optimized geometry of the cutting edges. Herein, WC with 17 wt% Co is processed by LPBF with a powder-bed heating of 900 degrees C. Afterwards microstructure, density, and hardness are determined. In addition, X-ray diffraction (XRD) analysis is performed to determine the phase composition. To investigate the edge-holding properties of LPBF-manufactured WC-Co cutting tools, stock removal tests are conducted on three different workpiece materials.