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Title: Mechanical properties of dissimilar metal joints composed of DP 980 steel and AA 7075-T6

In this study, a solid state joining process, called friction bit joining, was used to spot weld aluminium alloy 7075-T6 to dual phase 980 steel. Lap shear failure loads for specimens without adhesive averaged ~10kN, while cross-tension specimens averaged 2·8 kN. Addition of adhesive with a thickness up to 500 μm provided a gain of ~50% to lap shear failure loads, while a much thinner layer of adhesive increased cross-tension failure loads by 20%. Microstructures of the welds were martensitic, but the hardness of the joining bit portion was greater than that of the DP 980, owing to its higher alloy content. Softening in the heat affected zone of a welded joint appeared to be relatively small, though it was enough to cause nugget pullout failures in some lap shear tension specimens. Finally, other failures in lap shear tension were interfacial, while all of the failures in cross-tension were interfacial.
 [1] ;  [2] ;  [1] ;  [2]
  1. Brigham Young Univ., Provo, UT (United States). Manufacturing Engineering Technology
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Science and Technology of Welding and Joining
Additional Journal Information:
Journal Volume: 20; Journal Issue: 3; Journal ID: ISSN 1362-1718
Taylor & Francis
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
Country of Publication:
United States
36 MATERIALS SCIENCE; dissimilar material joining; aluminum alloy 7075-T6; dual phase 980; friction bit joining; mechanical properties; adhesive
OSTI Identifier: