Abstract

The concept of high-entropy alloys (HEAs) has revolutionized traditional alloy design, providing a foundation for the development of high-performance materials. On the other hand, composite material brings another possible approach to further improve the performance of HEAs. In this research, the tribological behaviors and wear mechanisms of three AlCoCrFeNi-based HEA coatings with novel composite phases (i.e., MnCoCrFeNi, Ni/C (nickel-coated graphite) and Cr respectively) and a single AlCoCrFeNi coating were investigated by model SRVIV friction and wear tester, micro-beam X-ray diffraction (XRD), Raman spectrometer, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The study suggests that incorporating a small amount of MnCoCrFeNi into the AlCoCrFeNi HEA coating markedly enhances lubrication, though the composite coating demonstrated comparatively severe wear; MnCoCrFeNi HEA shows evident friction reduction effect as a solid lubricant. The addition of a small amount of Ni/C composite phase gives the AlCoCrFeNi-based coating better friction reduction performance than adding MnCoCrFeNi, while the small addition of Cr greatly enhances the wear resistance of the HEA coating (by an order of magnitude). The differences in the addition of composite phase in a small amount leads to significant changes in the tribological behaviors of AlCoCrFeNi-based coatings. This work also provides a detailed analysis on the complex wear behaviors that actually occurred at the sliding interfaces of the four coatings, based on the perspective of the combination and collaboration of multiple mechanisms. Briefly, due to the differences in composite phases (or no composite phase), the four AlCoCrFeNibased coatings surprisingly exhibit wear behaviors mainly dominated by adhesive wear, abrasive wear, delamination wear and oxidative wear, separately. Beyond HEA formulation, the choice of composite phases is also a highly effective approach to enhancing the anti-wear and/or friction reduction performance of HEA coatings.

Keywords Plus：MICROSTRUCTURE，GRAPHITE，RESISTANCE，OXIDATION

Published in TRIBOLOGY INTERNATIONAL，Volume211；10.1016/j.triboint.2025.110839，NOV 2025