Enhanced mechanical properties of fine-grained polycrystalline diamond compact doping with nano‑vanadium carbide

In this study, fine-grained (0-2 μm) polycrystalline diamond compacts (PDC) doped with 0.5 wt% nano‑vanadium carbide (VC) addition were sintered under high pressure and high temperature (HPHT, 6GPa and 1600 °C). The effect of VC on the phase composition, microstructure and mechanical properties of fine-grained PDC has been systematically studied. The results showed that the hardness and impact resistant energy of the PDC samples doped with VC were 66.65GPa and 160 J, increased by 8.7% and 100%, respectively. The samples exhibited higher wear resistance, and the wear ratio of 5 passes, 10 passes and 15 passes were 60 × 104, 54.3 × 104 and 52.2 × 104，increased by 8.2%, 65.4% and 65.5%, respectively. The enhanced of hardness and wear resistance can be attributed that VC as a harder material occupied the space of cobalt in the polycrystalline diamond table and reduced the cobalt and η-phase Co3W3C content. At the same time the VC refined the tungsten carbide (WC) gains and made them more homogeneous dispersed in the polycrystalline diamond table. VC and WC formed solid solution dispersed in the binder to produce the pinning effect, which change the fracture mode to improve the impact resistance of PDC.