J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (5): 784-789.DOI: 10.1016/j.jmst.2018.10.027

• Orginal Article • Previous Articles     Next Articles

On the double-side probeless friction stir spot welding of AA2198 Al-Li alloy

Q. Chua, W.Y. Lia?(), H.L. Houb, X.W. Yanga, A. Vairisac, C. Wangb, W.B. Wangb   

  1. a State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Friction Welding Technologies, Northwestern Polytechnical University, Xi’an,710072, China;
    b Beijing Aeronautical Manufacturing Technology Research Institute, Beijing, 100024, China
    c Mechanical Engineering Department, TEI of Crete, Heraklion, Crete, 71004, Greece
  • Received:2018-03-25 Accepted:2018-05-24 Online:2019-05-10 Published:2019-02-20
  • Contact: Li W.Y.
  • About author:

    1 These authors contribute equally to this paper.


Double-side probeless friction stir spot welding (DP-FSSW) of AA2198 alloy was conducted to investigate the microstructure and mechanical properties. Compared with common single-side probeless friction stir spot welding (P-FSSW), the plastic strain during DP-FSSW is nearly symmetrical with respect to the bondline to suppress the extension of hook defect, which is detrimental to the joint mechanical strength. With DP-FSSW, a fully metallurgically bonded region has formed due to severe plastic deformation at high temperatures. Tensile/shear tests show that the joint strength could exceed 8kN, which is comparable to P-FSSW and refill FSSW, and all fractures happen in a shear failure mode as cracks extend along the interface of two sheets. The microhardness profile exhibits a uniform distribution along the thickness direction, in which the hook defect shows the lowest value.

Key words: Friction stir welding, Double-side, Al-Li alloy, Microstructure, Mechanical property