Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding

Refill friction stir spot welding is a promising joining process in lightweight design. As lightweight structures react sensitively to cyclic loads, the fatigue life of the joints are of particular interest. In previous studies, attempts have been made to optimize the fatigue properties based on pro...

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Main Authors: Niklaas Becker, Daniel Kuhn, Jan Piochowiak, Benjamin Klusemann
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S223878542500715X
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author Niklaas Becker
Daniel Kuhn
Jan Piochowiak
Benjamin Klusemann
author_facet Niklaas Becker
Daniel Kuhn
Jan Piochowiak
Benjamin Klusemann
author_sort Niklaas Becker
collection DOAJ
description Refill friction stir spot welding is a promising joining process in lightweight design. As lightweight structures react sensitively to cyclic loads, the fatigue life of the joints are of particular interest. In previous studies, attempts have been made to optimize the fatigue properties based on process parameter modification albeit with moderate success. The introduction of post-processing steps such as laser-shock or hammer peening resulted in an improvement but also in a considerable higher effort. In this work, a new approach is pursued, namely to increase the fatigue life properties by manipulating the residual stresses already during the welding process. This is achieved by milling a pocket into one of the joining surfaces prior to the welding process. The pocket and the clamping forces that occur during the welding process cause an elongation of the material. After releasing the clamping force, the elastic springback effect causes compressive forces, leading to compressive residual stresses in the spot weld. This has made it possible to increase the endurance limit for shear-loaded samples by a factor of 40 and for cross-tension-loaded samples by a factor of 18.
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institution OA Journals
issn 2238-7854
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publishDate 2025-05-01
publisher Elsevier
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series Journal of Materials Research and Technology
spelling doaj-art-77c76aa2db9c42ceb5c33a3954cc7b002025-08-20T02:25:35ZengElsevierJournal of Materials Research and Technology2238-78542025-05-01362951295910.1016/j.jmrt.2025.03.205Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot weldingNiklaas Becker0Daniel Kuhn1Jan Piochowiak2Benjamin Klusemann3Helmholtz-Zentrum Hereon, Institute of Materials Mechanics, Solid State Materials Processing, Max–Planck-Straße 1, 21502 Geesthacht, Germany; Corresponding author.Siemens Mobility GmbH, Duisburger Straße 145, 47829 Krefeld, GermanySiemens Mobility GmbH, Duisburger Straße 145, 47829 Krefeld, GermanyHelmholtz-Zentrum Hereon, Institute of Materials Mechanics, Solid State Materials Processing, Max–Planck-Straße 1, 21502 Geesthacht, Germany; Leuphana University of Lüneburg, Institute for Production Technology and Systems, Universitätsallee 1, 21335 Lüneburg, GermanyRefill friction stir spot welding is a promising joining process in lightweight design. As lightweight structures react sensitively to cyclic loads, the fatigue life of the joints are of particular interest. In previous studies, attempts have been made to optimize the fatigue properties based on process parameter modification albeit with moderate success. The introduction of post-processing steps such as laser-shock or hammer peening resulted in an improvement but also in a considerable higher effort. In this work, a new approach is pursued, namely to increase the fatigue life properties by manipulating the residual stresses already during the welding process. This is achieved by milling a pocket into one of the joining surfaces prior to the welding process. The pocket and the clamping forces that occur during the welding process cause an elongation of the material. After releasing the clamping force, the elastic springback effect causes compressive forces, leading to compressive residual stresses in the spot weld. This has made it possible to increase the endurance limit for shear-loaded samples by a factor of 40 and for cross-tension-loaded samples by a factor of 18.http://www.sciencedirect.com/science/article/pii/S223878542500715XRefill friction stir spot weldingFatigue lifeResidual stressAA6005A-T6
spellingShingle Niklaas Becker
Daniel Kuhn
Jan Piochowiak
Benjamin Klusemann
Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
Journal of Materials Research and Technology
Refill friction stir spot welding
Fatigue life
Residual stress
AA6005A-T6
title Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
title_full Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
title_fullStr Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
title_full_unstemmed Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
title_short Fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
title_sort fatigue life enhancement via residual stress engineering due to local forming during refill friction stir spot welding
topic Refill friction stir spot welding
Fatigue life
Residual stress
AA6005A-T6
url http://www.sciencedirect.com/science/article/pii/S223878542500715X
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AT janpiochowiak fatiguelifeenhancementviaresidualstressengineeringduetolocalformingduringrefillfrictionstirspotwelding
AT benjaminklusemann fatiguelifeenhancementviaresidualstressengineeringduetolocalformingduringrefillfrictionstirspotwelding