The expected excellent tribological performance of high-entropy alloys (HEAs) is rarely achieved due to the absence of self-lubricating ability on the worn surface. In particular, the situation is more challenging in HEAs with face-centered cubic structure because of the inferior yield strength when used in dry sliding conditions. Unlike conventional soft-solid lubricants, which deteriorate the mechanical properties of HEA matrix, in this study we demonstrate in a protocol model alloy that the proper incorporation of few-layer graphene as reinforcement in CoCrFeNiMn can lead to both surface strengthening and lubrication. This is achieved by a partially chemical interface reaction between graphene and HEA via a tunable fabrication process, resulting in a reduction of wear rate and friction coefficient of 86.03% and 23.87%, respectively. As a result of the interfacial in-situ carbide strengthening together with the self-lubrication of graphene, this tailored composite structure also exhibits superior tribological properties over most HEA-based self-lubrication composites. Besides, the subsurface structure evolution and deformation mechanisms that influence the wear resistance are systematically clarified through microscopic exploration and atomistic simulation. The present study presents an effective strategy for the development of innovative HEA composites suitable for safety-critical applications, which overcomes the inherent compromise and achieves exceptional tribological performance, i.e., self-lubricating and anti-wear.

中文翻译：

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石墨烯增强高熵合金复合材料的鲁棒耐磨性能

由于磨损表面缺乏自润滑能力，高熵合金（HEA）很少能达到预期的优异摩擦学性能。特别是面心立方结构的 HEA 的情况更具挑战性，因为在干滑动条件下使用时屈服强度较差。与传统的软固体润滑剂会降低 HEA 基体的机械性能不同，在这项研究中，我们在协议模型合金中证明，在 CoCrFeNiMn 中适当加入几层石墨烯作为增强材料可以实现表面强化和润滑。这是通过可调制造工艺，通过石墨烯和 HEA 之间的部分化学界面反应来实现的，从而使磨损率和摩擦系数分别降低 86.03% 和 23.87%。由于界面原位碳化物强化以及石墨烯的自润滑作用，这种定制的复合材料结构还表现出优于大多数 HEA 基自润滑复合材料的摩擦学性能。此外，通过微观探索和原子模拟，系统地阐明了影响耐磨性的地下结构演化和变形机制。本研究提出了一种开发适用于安全关键应用的创新 HEA 复合材料的有效策略，该策略克服了固有的妥协并实现了卓越的摩擦学性能，即自润滑和抗磨损。