High-temperature tribological behavior of CoCrFeNiV high-entropy alloys: A parallel comparison with CoCrFeNiMn high-entropy alloys

Abstract

The present work investigates the high-temperature tribological behavior of CoCrFeNiV fabricated by vacuum hot pressing sintering, and parallel experiments were conducted with CoCrFeNiMn as a comparison. It was found that the wear rate of CoCrFeNiV is almost an order of magnitude lower than for CoCrFeNiMn. Compared with CoCrFeNiMn of a single FCC, the precipitation of the hard sigma (σ) phase from the addition of V element made CoCrFeNiV possess excellent hardness (975 ± 11 HV) and high-temperature wear-resistance. The detailed characterization of the worn surface revealed that mild adhesion and oxidative wear are the dominant wear mechanisms of CoCrFeNiV. With the increase of temperature, the tribo-oxidation composed of V2O5, NiO and Cr2O3 play an excellent anti-oxidation lubrication role during the friction process. The higher volume fraction of the hard σ phase and the dense oxide glaze layer resulted in wear of approximately 0.289 × 10–4 mm3/Nm at 800 °C.