Improvement of corrosion resistance of AA2024-T3 using femtosecond laser peening without protective and confining medium

Highlights: • Femto Laser Shock Peening (fLSP) substantially enhances corrosion resistance. • Development of water repellency correlates with corrosion resistance. • Femto LSPed surface indicate reduced corrosion activity and long-term stability. • With fLSPed sample reduction in pitting and complete eradication of IGC attack. - Abstract: This work reports for the first time the effect of femtosecond laser shock peening (fLSP) without a sacrificial overlay under atmospheric conditions (no confinement) on the corrosion behaviour of AA2024-T3. After fLSP and additional exposure to air a superhydrophobic state (θ=160 ± 4°) is achieved. Moreover, fLSPed corrosion-resistant surface contributes to increased polarization resistance, reduced corrosion current and lower anodic dissolution, with long-term stability in aggressive chloride solution. Furthermore, SEM/EDS characterisation reveals reduction in pitting and complete eradication of intergranular corrosion (IGC) attack due to reduced metal/electrolyte contact area and homogeneous, refined microstructure which prevents chain-link IGC propagation.