The high strength of a thin plate surface produced by peening treatment is not yet used in
industrial products, even when the mechanical properties are improved, due to warpage after the
surface treatment. In this study, we focused on multifunction cavitation technology (MFC), which
improves various properties while suppressing surface roughness compared with conventional
peening treatment. Thin plate samples of four aluminum alloys, A1050, A2017, A5052, and A6061,
were used, and the surface of samples 1 mm thick was treated with MFC. The surface roughness
increased slightly for each sample, and the hardness and compressive residual stress increased except
for A1050. The amount of warpage was reduced in A6061, which is the hardest aluminum alloy used
in this study. Furthermore, the tensile strength of the MFC-treated sample decreased in A2017, but
increased in A5052 and A6061. These results showed that MFC-treated A5052 and A6061 are most
likely to be strengthened.