Friction and wear of metallic materials are ubiquitous in modern life, resulting in significant energy consumption and property damage. The tribological performance of metallic materials is greatly affected by their surface characteristics, motivating the rapid development of surface treatment technology. As a simple method without changing the matrix composition, mechanically induced surface nanocrystallization has emerged as a promising strategy to achieve reduced friction coefficients and increased wear resistance for metals. This review highlights the systemic progress and prospects of mechanically induced surface nanocrystallization, emphasizing its impact on mitigating friction and wear in metals. The review begins by presenting various processing techniques for preparing surface nanostructures, followed by an in-depth discussion on the mechanisms of mechanically induced surface nanocrystallization and the effects of processing techniques and their parameters on surface nanocrystallization. Then, several methods for stabilizing nanocrystalline structures are briefly introduced. Furthermore, the review thoroughly examines the influence of surface nanocrystallization on the tribological properties and the underlying mechanisms. Finally, the potential applications and challenges of surface nanostructured configurations in friction and wear-related fields are thoroughly discussed. 

The aim of this study is to fabricate the nanocomposite with low friction and high wear resistance using binary solid lubricant particles. The microstructure and tribological performance of the nanocomposite are evaluated, and the composition and film thickness of the lubricating film are observed and analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The nanocomposite exhibited improved tribological properties with a friction coefficient as low as 0.12 and a low wear rate of 2.17 × 10^-6 mm³/(N·m) in high-purity nitrogen atmosphere. Decreasing sliding speed can increase lubricating film thickness, and the thickest lubricating film is approximately 125 nm. As the film thickness of the lubricating film exceeded 90 nm, the friction coefficient curves became smooth. In compared with WS₂, MoS₂ can be more effective in forming the transfer layer on the worn surfaces at the initial stage of the tribological process.