Falah, MohsenMohsenFalahLau, RobertRobertLauSpalek, NiclasNiclasSpalekSeidelmann, MarenMarenSeidelmannLalkovski, NikolayNikolayLalkovskiRutner, MarcusMarcusRutner2025-12-172025-12-172025-12-1011th International Conference on Fatigue Design, FatDes 2025https://hdl.handle.net/11420/60229In recent years, the adoption of Wire Arc Additive Manufacturing (WAAM), now defined as Directed Energy Deposition based on Gas Metal Arc Welding (DED-Arc), in steel construction has increased significantly. However, the sequential layer deposition inevitably creates surface notches that cause high stress concentrations, leading to fatigue crack initiation. The current industrial standard for post-processing, CNC milling, is time-consuming and resource-intensive. A novel research approach focuses on directly controlling critical residual stresses of as-built specimens by introducing near-surface compressive residual stresses using a Cu/Ni nanostructured metallic multilayer (NMM). This study investigates the effect of NMM on DED-Arc structures and extends its application to metallic 3D-printed components. Optical microscopy provides detailed surface morphology and reliable roughness measurements, while X-ray diffraction (XRD) confirms the presence of residual tensile stresses in the NMM and the resulting residual compressive stresses in the steel substrate. Preliminary tension-tension fatigue testing provides insights into the fatigue strength increase due to NMM treatment of DED-Arc dogbone specimen.en2452-321620251018Elsevier BVhttps://creativecommons.org/licenses/by-nc-nd/4.0/Nanometallic MultilayerPost-Print TreatmentDirected Energy Deposition based on Gas Metal Arc Welding (DED-Arc)Fatigue ResistanceLifetime ExtensionTechnology::620: Engineering::620.1: Engineering Mechanics and Materials Science::620.11: Engineering MaterialsTechnology::620: Engineering::620.5: NanotechnologyJournal Articlehttps://doi.org/10.15480/882.1632010.1016/j.prostr.2025.11.00210.15480/882.16320Journal Article