Abstract: Ag-Cu alloys are extensively used in sliding electric contacts due to their superior electrical conductiv-ity, but their limited wear resistance reduces component longevity. Surface severe plastic deformation (SSPD) has emerged as a promising method to enhance wear resistance and reduce friction of metals without altering the matrix composition. In this study, an Ag-20 wt.%Cu alloy was subjected to SSPD for various durations, with the aim of improving tribological performance. The microstructure, hardness, and current-carrying tribological performance under different currents were systematically investigated, along with an exploration of the underlying mechanisms. The results show that in addition to introduc-ing a high density of dislocations on the surface, SSPD also encourages the formation of (111) texture, and particularly disperses the initially long strips of Cu-rich phase into short strips and fine particles. It promotes a tribo-film composed primarily of a mixture of Cu2 O and CuO that forms on the worn surface of the surface-treated sample under the 1 A current, thus significantly reducing the friction coefficient and electrical noise. Under the 10 A current, the sample treated for 60 min possesses the optimal fric-tion coefficient (0.429), wear rate (0.791 ×10-6 mm ³/(N m)), and electrical noise (0.240 V). In contrast to the Ag/Cu layered structure observed on the worn subsurface of the untreated sample, a single-phase Ag (Cu) solid solution forms on the worn subsurface of the 60-min treated sample, which improves the current-carrying tribological performance. This work provides valuable insights for the development and application of electrical contact alloys with excellent performance.

Key words: Ag-Cu alloy, Surface severe plastic deformation, Current-carrying friction, Microstructure evolution, Ag (Cu) supersaturated solid solution