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Surface and mechanical characterization of stationary shoulder friction stir welded lap joints: experimental and numerical approach

  • IJMF 10th Anniversary - Advances in Material Forming
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Abstract

Friction Stir Welding (FSW) is one of the most used solid-state welding processes in the aeronautical, aerospace, ground transportation and naval fields. Stationary Shoulder Friction Stir Welding (SSFSW) is a recently introduced variant of the process allowing lower heat input into the joints, with beneficial effects in terms of joint mechanical properties, microstructure and top surface finish. In the paper, lap joints produced by SSFSW and made out of AA6082-T6 aluminum alloy sheets have been analyzed with the aim to investigate the effect of the stationary shoulder on the lap joints surface, metallurgical, and mechanical properties. The lap joints produced by SSFSW have been compared to the ones produced by “conventional” FSW in order to highlight the differences between the two processes. The top surface of the joints obtained with the two processes has been quantitatively evaluated. Finally, a dedicated numerical model has been utilized to highlight the causes of the observed differences through the distributions of the main field variables, namely temperature, strain and strain rate. It was found that SSFSW results in narrower weld nugget and smaller areas involved by micro hardness reduction caused by smaller peak temperature and high temperature zone. Additionally, better surface quality was found for the joint welded by SSFSW with lower heights and flash, allowing to avoid subsequent finishing operations needed for most industrial applications.

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Acknowledgements

Authors sincerely acknowledge FPT Industrie S.p.A. for supporting this research activity, providing the base materials and significantly helping in the joints production.

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Authors and Affiliations

  1. Department of Industrial and Digital Innovation, University of Palermo, Viale delle Scienze, 90128, Palermo, Italy

    Gianluca Buffa, Livan Fratini & Attilio Masnata

  2. Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125, Naples, Italy

    Filomena Impero, Fabio Scherillo & Antonino Squillace

Authors
  1. Gianluca Buffa
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  2. Livan Fratini
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  3. Filomena Impero
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Correspondence to Gianluca Buffa.

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Buffa, G., Fratini, L., Impero, F. et al. Surface and mechanical characterization of stationary shoulder friction stir welded lap joints: experimental and numerical approach. Int J Mater Form 13, 725–736 (2020). https://doi.org/10.1007/s12289-020-01574-9

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  • DOI: https://doi.org/10.1007/s12289-020-01574-9

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