Study on parameter optimisation for field-assisted sintering of fully-dense, near-nano WC–12Co

• Nearly fully-dense WC–12Co samples were produced by field assisted sintering technique.
• Mean WC grain sizes of the samples without grain growth inhibitors were below 200 nm.
• The effect of the sintering parameters on densification and microstructure was studied.
• High and low effect sintering parameters were identified.

A sintering route to fully-dense near-nanocrystalline WC–12Co without grain growth inhibitors was developed. The influence of sintering parameters on the densification, microstructure, and mechanical properties of the material compacted by Field Assisted Sintering Technology (FAST) was investigated. High and low-effect sintering parameters were identified, and a process to consolidate nearly fully-dense cemented carbide samples with mean grain sizes of about 200 nm was elaborated. The parameters of the sintering process were adapted in order to maximise densification on the one hand and, on the other hand, to avoid growth of the WC grains during the sintering process. Furthermore, the reproducibility of the sintering process with respect to densification was tested. Microscopic examination of the sintered samples showed a minimisation of inhomogeneity combined with maximisation of the relative density, while the impact of the sintering parameters on the microstructural parameters was found to be insignificant. X-ray diffraction (XRD) was applied to determine the phase composition and crystallite size of the sintered WC.