Mechanical and microstructural characterization of WC-Co consolidated by binder jetting additive manufacturing

A study was carried out to investigate the influence of the initial powder features on the microstructure, the phase composition, and on the mechanical properties of WC-12%Co samples produced by binder jetting and densified by sintering in vacuum at 1400 °C and by sinter-HIPing. The initial powder consisted of a mixture of fine-grained and coarse-grained WC-based particles, and W2C-based ones. The density of the printed samples was 97.4% and 99.3% after sintering and sinter-HIPing, respectively. Layer-oriented porosity was observed only in sintered samples. The microstructure of the samples consisted of a mixture of fine and coarse WC grains, which can be the result of the coalescence of grains from anomalous coarse grains in the powder particles. Vickers hardness and transverse rupture strength of sinter-HIPed samples are 1205 HV and 2257 MPa, respectively, which is coherent with the microstructural analysis and close to coarse-grained commercial products.