During wear, materials undergo chemical and mechanical changes that lead to the formation of what are known as ‘third bodies’. Tribologists have long understood that third bodies have significant influence on the friction and wear performance of materials. However, the inhomogeneous nature of third bodies and how they form at the ‘buried interface’ of a sliding tribological contact has long made it difficult to fully characterize and study them. Recently, there have been significant advancements in nanomechanical testing such that researchers have begun to use these techniques to, for the first time, determine mechanical properties of third bodies. Coupling these measurements with high resolution electron microscopy and surface chemical analysis has finally given tribologists the ability to obtain the necessary data to understand and model third bodies and their connections to friction and wear. This review will present recent work on the topic of nanomechanical testing of third bodies while at the same time identifying the challenges and opportunities this research presents.

在磨损期间，材料会发生化学和机械变化，从而导致形成所谓的“第三体”。摩擦学家早就知道，第三种物体会对材料的摩擦和磨损性能产生重大影响。但是，第三体的不均匀性质以及它们在滑动摩擦接触的“埋入界面”中如何形成，长期以来一直使人们难以完全表征和研究它们。近来，纳米机械测试取得了重大进展，研究人员已开始使用这些技术来首次确定第三体的机械性能。最终，这些测量结果与高分辨率电子显微镜和表面化学分析相结合，使摩擦学家能够获得必要的数据，以理解和建模第三体及其与摩擦和磨损的联系。这篇综述将介绍有关第三主体的纳米力学测试的最新工作，同时确定本研究提出的挑战和机遇。