Effect of Ultrasonic Shot Peening on Surface Mechanical and Wear Behavior of Aluminum 7075-T651 Alloy

Aluminum alloys have gained widespread attention in various engineering sectors such as aerospace, automobile, and construction industries owing to their attractive properties. On the other hand, the tribological properties of aluminum alloys are of serious concern due to their limitation in terms of hardness. The objective of the current study was to enhance the surface mechanical properties including microhardness, compressive residual stress (CRS), and wear resistance of 7075-T651 aluminum alloy subjected to ultrasonic shot peening (USP). The samples of aluminum alloy were first treated with USP for various durations followed by different types of in-depth characterization. X-ray diffraction analysis was used to examine the bulk texture development after peening. The wear studies were carried out on a ball-on-plate wear testing machine under various applied loads. The results indicated an increase in hardness, surface roughness, and CRS of the samples with increasing USP time. Additionally, a marginal difference in the surface roughness of peened samples was observed for selected peening times. The wear depth and width of peened wear tracks were found to be less than those of un-peened ones. The surface tribological properties of the worn-out samples were studied using scanning electron microscopy (SEM). The elemental analysis was carried out using electron-dispersive spectroscopy (EDS).