Effect of Shot Peening on the Strength and Corrosion Properties of 6082-T651 Aluminium Alloy

This paper investigated the effect of shot peening on the strength and corrosion properties of 6082-T651 aluminium alloy. The microstructure, surface roughness, microhardness, residual stresses, and corrosion behaviour were investigated and compared with those of untreated aluminium alloy. Cracks and delaminations in the surface layer could only be seen on the treated specimens at a working pressure of 4 bar and 8 bar, while no such effect was observed at a working pressure of 1.6 bar. The surface roughness was increased more than 15 times after shot peening at a working pressure of 8 bar. Shot peening resulted in an increase in microhardness of 27% and a deeper layer with higher compressive residual stresses compared to the untreated specimens. All treated specimens exhibited improved corrosion resistance with a lower degree of anodic dissolution. The current density of the treated specimen with the lowest surface roughness was more than two-fold lower than that of the untreated specimen.