Improvement of the frictional behavior of Al 7075-T6 by ultrasonic-assisted ball burnishing process

Nowadays, 7000 series aluminum alloys, especially, Al 7075 have found extensive applications especially in aerospace industries. Compared to high-strength steel alloys, Al 7075 has exhibited desirable mechanical properties such as high specific strength. However, their corrosion susceptibility and poor abrasion properties have limited the application of these alloys. Complementary operations such as ultrasonic-assisted ball burnishing have been suggested to overcome these limitations. Therefore, in this study, a newly developed 28 kHz ultrasonic-assisted ball burnishing device was designed and fabricated. Then, the effect of burnishing process was experimentally assessed on surface roughness, surface hardness, grain size, friction coefficient, and wear rate of the workpieces made of Al 7075. The results reveal the greater effectiveness of the ultrasonic-assisted ball burnishing process compared to conventional burnishing processes, in terms of improvements in surface roughness, surface hardness, grain size, frictional behavior, and wear rate. The friction coefficient was declined by 36.09% in the case of ultrasonic-assisted ball burnishing which was remarkably higher than conventional burnishing process with 7.39% reduction.