Enhanced drilling performance of impregnated diamond bits by introducing a novel HEA binder phase

To address the challenges associated with the limited strength of conventional Cu-based binder phases and insufficient adhesion between the binder phase and diamond in impregnated diamond bits, a novel Cu35Ni25Co25Cr15 high entropy alloy-WC (HEA-WC) binder phase was designed and utilized to prepare impregnated diamond composites and bits. A comparative investigation was performed to evaluate the effect of the HEA-WC binder phase on the drilling performance of impregnated diamond bits, as compared to those prepared using the conventional 663Cu-20wt.%Co-WC (663Cu-Co-WC) binder phase. The results reveal that the HEA-WC possessed superior mechanical properties than the 663Cu-Co-WC alloy, moreover, the composites fabricated using the HEA-WC binder phase exhibited a higher hardness and transverse rupture strength. During the sintering process, the HEA-WC binder phase reacted with diamond at the interface, resulting in the formation of M7C3 and M23C6 compounds, which facilitated chemical bonding and enhanced the adhesion between the HEA-WC binder phase and diamond. Consequently, the diamond in the impregnated composites displayed improved protrusion height and self-dressing characteristics in comparison with the composites with the 663Cu-Co-WC binder phase. Furthermore, the impregnated diamond bits incorporating the HEA-WC binder phase demonstrated significantly lower mechanical specific energy and reduced wear velocity. These findings suggest that the HEA-WC binder phase enhances the operational efficiency and extends the service life of impregnated diamond bits.