Exploring the boundaries of refill friction stir spot welding: influence of short welding times on joint performance

Jonathan Draper*, Sebastian Fritsche, Andrew Garrick, S. T. Amancio-Filho, Athanasios Toumpis, Alexander Galloway

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Refill friction stir spot welding is a solid-state spot-welding technique suited to lap joining of thin aluminium sheets, including difficult-to-weld 2xxx series alloys that are prone to hot cracking during fusion welding processes. Long welding time is an ongoing challenge that hinders industrial adoption of the process. To address this, the present study explores much shorter welding times than those previously reported in the literature and assesses the impact on joint quality. Joints of 1.8 mm thick AA2024-T3 sheet were produced with welding times from 3 s, down to 0.75 s and rotational speeds of 1000 rpm to 2500 rpm. Defect formations within the welds were studied with the aid of optical microscopy. The mechanical properties were evaluated using tensile lap shear testing and microhardness mapping, and failure modes were characterised using scanning electron microscopy. Various weld defects were found at all welding times and rotational speeds, and the defects enlarged with decreasing welding time and increasing RS. The highest lap shear strength of 9.21 kN was achieved with a welding time of 3 s and rotational speed of 2000 rpm; lap shear strengths of 7.02 kN and 6.37 kN were achieved for 1.5 s and 0.75 s welds, respectively.
Original languageEnglish
Pages (from-to)1801-1813
Number of pages13
JournalWelding in the World
Volume68
Issue number7
Early online date28 Feb 2024
DOIs
Publication statusPublished - Jul 2024

Keywords

  • Aerospace materials
  • Aluminium alloys
  • Friction welding
  • Refill friction stir spot welding
  • Solid-state joining

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

Fields of Expertise

  • Advanced Materials Science

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