Study on the wear resistance of 2024-T351 aluminum alloy strengthened by ultrasonic-assisted laser shock peening

Abstract

The ultrasonic-assisted laser shock peening (ULP) technique, through the combined strengthening effects of laser shock peening and ultrasonic peening, can enhance the wear resistance and fatigue resistance of metal materials. This paper uses the 2024-T351 aluminum alloy as the subject for ULP enhancement experiments. Comprehensive tests including microstructure, phase structure, surface morphology, microhardness, residual stress, and wear resistance were conducted. Furthermore, coefficient of friction (COF), wear volume loss, and wear morphology were analyzed to reveal the improvements in wear resistance and the transformations in wear mechanisms induced by ULP treatment. Significant grain refinement and high-density dislocations are induced by ULP treatment, which results in pronounced work hardening effects, achieving a surface microhardness of 191.9 HV and a hardened layer depth of 850 µm. Compared to the untreated samples, the high-hardened surface induced by ULP reduces the possibility of material peeling from the surface, leading to a decrease in average COF and wear volume loss by up to 37.9% and 40.8%, respectively. Additionally, the ULP treatment effectively suppress adhesive wear, significantly improving the wear morphology and enhancing the wear resistance of the aluminum alloy.