Friction and wear behaviors of boron-containing high entropy alloy/diamond composites

In present work, FeCoCrNiB0.15 high-entropy alloy (HEA) with its diamond composite were prepared by spark plasma sintering (SPS) technique at 950 °C. FeCoCrNiMo0.15 and its diamond composite samples were prepared for comparison. The phase composition and microstructures of FeCoCrNiMo0.15 and FeCoCrNiB0.15 HEAs and diamond composite samples were investigated, and the friction and wear behaviors of the HEAs and diamond composites against Si3N4 balls under dry sliding condition in ambient air were compared on a ball-on-disk tester. The results showed that, Cr-rich phase precipitated from the metastable FCC matrix was observed in both HEAs. The relative density of the FeCoCrNiMo0.15 and FeCoCrNiB0.15 alloy samples was ~93.1 % and ~ 98.4 %, respectively, while the Vickers hardness of the samples was 309.7 ± 10.6 HV1 and 317.5 ± 8.4 HV1, respectively. The wear resistance of FeCoCrNiB0.15 was higher than that of FeCoCrNiMo0.15 alloy, and the grinding rate of FeCoCrNiB0.15/diamond composite against Si3N4 was higher than that of the FeCoCrNiMo0.15/diamond composite. With detailed microstructural analyses, the possible friction and wear mechanism were discussed. Present study shows that the boron-doped HEA matrix in diamond composites is a promising candidate for fabricating diamond tools with long service life and high processing efficiency.