Materials can suffer mechanical fatigue when subjected to cyclic loading at stress levels much lower than the ultimate tensile strength, and understanding this behaviour is critical to evaluating long-term dynamic reliability. The fatigue life and damage mechanisms of two-dimensional (2D) materials, of interest for mechanical and electronic applications, are currently unknown. Here, we present a fatigue study of freestanding 2D materials, specifically graphene and graphene oxide (GO). Using atomic force microscopy, monolayer and few-layer graphene were found to exhibit a fatigue life of more than 10⁹ cycles at a mean stress of 71 GPa and a stress range of 5.6 GPa, higher than any material reported so far. Fatigue failure in monolayer graphene is global and catastrophic without progressive damage, while molecular dynamics simulations reveal this is preceded by stress-mediated bond reconfigurations near defective sites. Conversely, functional groups in GO impart a local and progressive fatigue damage mechanism. This study not only provides fundamental insights into the fatigue enhancement behaviour of graphene-embedded nanocomposites, but also serves as a starting point for the dynamic reliability evaluation of other 2D materials.

当在远低于极限抗拉强度的应力水平下承受循环载荷时，材料会遭受机械疲劳，了解这种行为对于评估长期动态可靠性至关重要。对于机械和电子应用而言，二维 (2D) 材料的疲劳寿命和损伤机制目前尚不清楚。在这里，我们介绍了独立式二维材料的疲劳研究，特别是石墨烯和氧化石墨烯 (GO)。使用原子力显微镜，发现单层和少层石墨烯的疲劳寿命超过 10 ⁹平均应力为 71 GPa，应力范围为 5.6 GPa，高于迄今为止报道的任何材料。单层石墨烯的疲劳失效是全局性的和灾难性的，没有进行性损伤，而分子动力学模拟表明，在缺陷位点附近发生应力介导的键重新配置之前。相反，GO 中的官能团赋予局部和渐进的疲劳损伤机制。该研究不仅为石墨烯嵌入纳米复合材料的疲劳增强行为提供了基本见解，而且还作为其他二维材料动态可靠性评估的起点。