Magnetic-assisted laser shock peening of 7075-T6 aluminum alloy

In this study, an innovative process, magnetic–assisted laser shock peening (MA-LSP), was used to strengthen 7075-T6 aluminum alloy. In the MA-LSP process, the target sample is placed in a magnetic field during laser shock peening. The effects of MA-LSP treatment and conventional LSP treatment were compared to explore the influence of magnetic field on the peening effect. The results showed that the surface peening indentations were deeper after MA-LSP treatment than after conventional LSP, indicating a greater impact energy received. After MA-LSP, the surface grains were more obviously refined, the surface hardness was significantly improved, and a deeper hardened layer was produced. In-depth residual stress tests indicated a greater surface compressive residual stress of the sample after MA-LSP, and the compressive residual stress layer of the sample was also deeper. In addition, the sample exhibited greater strength following MA-LSP. It is believed that both magnetoplasticity and the constraining effect exerted by the magnetic field on plasma expansion play a role in enhancing the peening effects.