Properties of WC-8Co hardmetals with plate-like WC grains prepared by plasma-assisted milling

WC-8Co hardmetals with different proportions of prismatic WC grains and plate-like WC grains were directly produced through sintering the W-C-8Co ele- mental powder mixture which was fabricated by dielectric barrier discharge plasma （DBDP）-assisted milling. The morphology of prepared WC-8Co hardmetals, geometry and the preferential orientation of plate-like WC were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM） analysis. The results demon- strate that the microstructure and mechanical properties of the sintered hardmetals are related to the morphology of W grain which is dependent on DBDP-milling time. The DBDP for 1 h （DBDP-1 h）-milled W-C-Co powder contains granular W particles that tend to form prismatic WC grains, while the DBDP for 3 h （DBDP-3 h）-milled powder contains lamellar W particles that generate plate-like WC grains. By adjusting the weight ratio of DBDP-1 h powder and DBDP-3 h powder in W-C-8Co mixture, the proportion of plate-like WC in the hardmetals can be controlled, and relatively high transverse rupture strength （TRS） is obtained as the proportion of plate-like WC grain in the hardmetals is about 35 % in present experimental condition.