Hamburg University of Technology, Hamburg, Germany
Niclas Spalek
Biography
With his materials science background and history in surface technology, Niclas Spalek is currently pursuing his PhD at the Hamburg University of Technology at the Institute for Metal and Composite Structures under Prof. Rutner. His research is dedicated to enhancing the fatigue strength of steel-based structures through the development and optimization of an innovative post-weld treatment. His work bridges the gap between civil engineering and material science for sustainable use of current and newly constructed infrastructure.
Conferences
Room |
Date |
Hour |
Subject |
|---|---|---|---|
| Room 7 |
20-11-2025 |
8:30 am – 9:00 am |
124 Material mechanisms of the nanostructured metallic multilayer post-weld treatment for fatigue strength increase |
Conferences Details
124 Material mechanisms of the nanostructured metallic multilayer post-weld treatment for fatigue strength increase
While traditional post weld treatments intend to reduce the fatigue failure potential by changing the weld seam geometry, introduction of compressive residual stresses and shielding of environmental impacts, the nanostructured metallic multilayer (NMM) covers all three mechanisms simultaneously. NMM offer combined high strength and ductility and significantly enhanced fatigue resistance1-4.
In a recent study we detected a strong enhancement in fatigue resistance of the weld through applied NMM and a small scatter of results indicating a high reliability of the method3-5. Through XRD testing at the P61A-beamline at the German Synchrotron (DESY) we understood that residual stresses, which are generated through the deposition process, play a major role in enhancing the fatigue resistance of the weld. Tensile stress in the nanolaminate causes beneficial compressive stress in the substrate which counteracts fatigue crack initiation resulting in an unmatched increase in fatigue strength. NMM treatment of the double V weld increases the fatigue strength from FAT class 80 to beyond 190. This paper investigates under which conditions and controlled by which parameters the tensile stress distribution in the nano multilayer is optimized, paving the way for NMM to reliably and economically contribute to longevity and reduced maintenance of cyclically loaded metal infrastructure.
References
1. Stoudt, M., Ricker, R. & Cammarata, R. The influence of a multilayered metallic coating on fatigue crack nucleation. International Journal of Fatigue 23, 215–223; 10.1016/S0142-1123(01)00153-0 (2001).
2. Kaneko, Y., Nishijima, Y., Sanda, T. & Hashimoto, S. Fatigue Life Enhancement by Surface Coating of Ni/Cu Multilayered Films. MSF 561-565, 2393–2398; 10.4028/www.scientific.net/MSF.561-565.2393 (2007).
3. Brunow, J., Spalek, N., Mohammadi, F., Rutner, M. A novel post-weld treatment using nanostructured metallic multilayer for superior fatigue strength. Scientific reports 13, 22215; 10.1038/s41598-023-49192-0 (2023).
4. Rutner, M., Spalek, N., Falah, M., Lalkovski, N. Verknüpfung von Nano mit Makro – Chancen für den Stahlbau. Stahlbau 93, 584–596; 10.1002/stab.202400048 (2024).
5. Brunow, J., Gries, S., Krekeler, T., Rutner, M. Material mechanisms of Cu/Ni nanolaminate coatings resulting in lifetime extensions of welded joints. Scripta Materialia 212 (2022).
