<p>This study examines the impact of the number of equal channel angular pressing (ECAP) passes on the tribological properties of A390 aluminum alloy. Specifically, the investigation focuses on how microstructural features, including the roundness and size of second-phase particles, the volume fraction and distribution of intermetallic compounds, the grain size of the aluminum matrix, the density of geometrically necessary dislocations, and the proportion of high-angle grain boundaries, influence wear characteristics such as volume loss, specific wear rate, and friction coefficient. The worn wear surfaces were analyzed, and the main wear mechanisms were investigated for various specimens. The findings indicated that the most significant microstructural refinement occurred during the initial two ECAP passes. The volume loss increased after the first pass but decreased sharply after the second pass, with subsequent ECAP passes having a negligible effect on volume loss. The specimen subjected to the fourth ECAP pass exhibited the lowest specific wear rate (0.00024&#xa0;mm³/N × m), the lowest average friction coefficient (0.24), and the lowest volume loss (11.7 × 10⁷&#xa0;μm³). As the number of ECAP passes increased, the dominant wear mechanism shifted from adhesive to abrasive wear, although instances of delamination and adhesive wear were still observed. Additionally, the fine debris generated during the tribological test acted as a lubricant, contributing to a reduction in the specific wear rate of the ECAP-processed specimens.</p>