Revealing the frictional behavior through the lens of structural and chemical evolution is crucial for comprehending the exceptional wear-resistance of alloys with complex composition. Here, we propose that superior wear resistance can be achieved via dynamic surface segregation during sliding at room temperature. This strategy was demonstrated in CrCoNi multi-principal element alloy (MPEA) films with nano-grain structure, which exhibit a remarkably low wear rate that is <50 % of that for their VCoNi counterpart. Such distinct wear behavior is attributed to the specific friction-driven Ni segregation on the CrCoNi surface, which facilitates the preferential oxidation and formation of a nanocomposite protective layer with equiaxed nanograins uniformly embedded in an amorphous matrix. This wear-induced unique microstructure accommodates sliding-induced plastic deformation against damage and is responsible for the superior wear-resistance. Having revealed these fundamental mechanisms by experiment and simulation, this study provides a brand-new perception for designing self-adaptive MPEA surfaces. This involves adjusting the evolution of deformation layers with specific structure and chemistry, precisely engineered for tribological applications.

中文翻译：

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通过摩擦驱动的表面偏析制备耐磨 CrCoNi 纳米晶薄膜


通过结构和化学演化的视角揭示摩擦行为对于理解复杂成分合金的卓越耐磨性至关重要。在这里，我们建议通过室温滑动过程中的动态表面偏析可以实现优异的耐磨性。这一策略在具有纳米晶粒结构的 CrCoNi 多主元合金 (MPEA) 薄膜中得到了证明，该薄膜表现出极低的磨损率，仅为 VCoNi 同类合金的 <50%。这种独特的磨损行为归因于CrCoNi表面上特定的摩擦驱动的Ni偏析，这有利于优先氧化并形成纳米复合材料保护层，其中等轴纳米颗粒均匀地嵌入非晶基体中。这种磨损引起的独特微观结构可适应滑动引起的塑性变形以抵抗损坏，并具有优异的耐磨性。本研究通过实验和仿真揭示了这些基本机制，为设计自适应MPEA表面提供了全新的认识。这涉及调整具有特定结构和化学性质的变形层的演变，并针对摩擦学应用进行了精确设计。