Improving the corrosion resistance of aluminum alloy welds through powder-ball combined ultrasonic shot peening

Aluminum alloy 5052 is used extensively in various industries, including aerospace, shipbuilding, and automotive manufacturing. Components made from this alloy often require welding treatments; however, in marine environments, these welds are susceptible to corrosion, which affects their durability and service life. In this study, power-ball combined ultrasonic shot peening (USSP) was used for surface-strengthening 5052 aluminum alloy welds. The resulting surface characteristics and corrosion resistance were examined, and the compared to the untreated sample, the USSP-treated sample showed a shift in the stress state from residual tensile stress (31.4 MPa) to residual compressive stress (-257.5 MPa). Immersion and electrochemical corrosion experiments confirmed that the formation of residual compressive stress and a gradient structure on the surface enhanced the corrosion resistance, which was substantiated by detailed characterization. The corrosion rate of the treated aluminum alloy weld sample (7.18 mu m/year) decreased by 72.90% compared with that of the untreated sample. The study findings indicate that the powder ball combined USSP is a potential method for improving the corrosion resistance of aluminum alloy welds in marine environments.