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The fatigue performance from pre-corroded pits was studied in laser-shock-peened AA7075-T651 with and without a protective ablation-layer. Surface and microstructural characterisation showed laser-shock-peening generated residual stresses up to −400MPa, limited hardness and moderate surface roughness increase. The laser-shock-peened specimens were exposed to 3.5 wt-% sodium chloride solution for different levels of galvanostatic control. The compressive residual stresses did not significantly affect corrosion behaviour, or corrosion pit morphology. Laser-shock-peening-induced surface roughness had the most detrimental impact on corrosion performance. Fatigue testing of pre-corroded AA7075-T651 showed pits act as stress concentrations. Cracks initiated shortly after dynamic loading, reducing fatigue life by 50%. Laser-shockpeening increased fatigue life by 400% compared to corroded-untreated AA7075-T651, due to residual stresses effectively counteracting stress concentrations produced by pits. Highlights• Pre-corroded laser-peened (LSP and LSPwC) AA7075-T651 fatigue performance is investigated. • XRD and incremental hole drilling show deeper compressive residual stresses for LSPwC compared to LSP. • Electrochemical tests show no significant changes in corrosion behaviour after laser peening.• Fatigue testing and fractography show compressive residual stresses effectively counteract stress concentrations at pits.

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Plain bend bars made from FV566 martensitic stainless steel were extracted from the root of ex‐service power plant turbine blades and several industry‐relevant notch geometries were introduced. Some of the samples were shot peened. The notched bend bars were loaded plastically in the low‐cycle fatigue regime and finite element (FE) modeling carried out to investigate the effects of changing notch geometry, combined with shot peening, on fatigue behaviors such as crack initiation, short crack growth, and coalescence. Shot peening damaged the notch surface, accelerating initiation behaviors, but had a lifetime‐extending effect by retarding short crack growth in all tested notch geometries. At a total strain range higher than 1.2%, the lifetime extension benefit from shot peening was diminished due to compressive residual stress relaxation in the notch stress field. Notch geometry (and the associated varying constraint levels and stress/strain gradients) was found to have no notable difference on fatigue life when tested at identical notch‐root strain ranges.

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