Strain-Dependent Wear Mechanism Transition and Regression-Based Validation of the Self-Lubricating Behavior in Accumulative Roll Bonding-Processed Al5052 Under Dry Sliding

Abstract

Severe plastic deformation improves the strength of aluminum alloys however, the mechanism responsible for enhanced wear resistance after ARB remains unclear. This study establishes a direct mechanistic correlation between ARB strain, wear-mode transition, and tribofilm evolution in Al5052. Multi-layered ARB-processed Al5052 sheets were tested under dry sliding against SS304 at normal loads of 10–30 N and sliding velocities of 0.12–0.36 m/s. Worn surfaces were examined using FE-SEM and EDS, while Raman was used to identify oxide phase formation. Regression modeling was performed to quantify parametric dependencies. The steady-state COF remained nearly unchanged within 0.22–0.26 for all processing conditions. In contrast, the wear rate decreased from 2.69 × 10−3 to 1.34 × 10−3 mm3/N·m after five ARB passes at 10 N and 0.12 m/s, corresponding to a 50.1% reduction. At 30 N and 0.36 m/s, the wear rate decreased from 3.98 × 10−3 to 2.01 × 10−3 mm3/N·m, showing a 49.4% reduction. FE-SEM revealed progressive suppression of delamination, cracking, and material pull-out with increasing ARB strain, while Raman spectra confirmed stronger Al2O3 and MgO signatures in higher-pass specimens. These results indicate a transition from severe adhesive-delaminative wear in the as-received alloy to a milder oxidative sliding regime after five ARB passes. Regression analysis confirmed prediction accuracy for friction and wear rate. Thus improved wear resistance was governed mainly by stabilized subsurface deformation.