Spalek, NiclasNiclasSpalekAbreu Faria, GuilhermeGuilhermeAbreu FariaDavydok, AntonAntonDavydokRutner, MarcusMarcusRutner2025-12-052025-12-052025-11-19Advanced Engineering Materials 28 (1): e202502357 (2026)https://hdl.handle.net/11420/59461Welded joints suffer from reduced fatigue life due to geometric stress concentrations and metallurgical changes in the heat-affected zone that promote crack initiation under cyclic loading. This study investigates a novel postweld treatment, utilizing a Cu/Ni nanometallic multilayer thin film deposited onto the welded butt joint. Deposition current densities and individual Cu/Ni layer thicknesses are systematically varied to optimize fatigue performance. A multiscale residual stress (RS) analysis characterizes stress states within individual multilayers and in the steel substrate, indicating all substrate RS are compressive in nature after thin film deposition. Results demonstrate a direct correlation between compressive RS magnitude and fatigue strength improvement. Tested at ΔσR = 0.75 × fy, a more than a 300% increase in cycles to failure is seen compared to the as-welded condition. This postweld treatment offers a promising approach for extending the operational life of welded structures across industrial applications.en1527-264820251Wiley-VCH Verl.https://creativecommons.org/licenses/by/4.0/electrodepositionfatigueinfrastructurelifetime extensionnanometallic multilayerpostweld treatmentthin filmsTechnology::620: Engineering::620.1: Engineering Mechanics and Materials ScienceTechnology::670: ManufacturingJournal Articlehttps://doi.org/10.15480/882.1627410.1002/adem.20250235710.15480/882.16274Journal Article