Joining AA7099 to Ni-Cr-Mo Steel Using Friction Stir Dovetailing

  • Md. Reza-E-RabbyEmail author
  • Scott Whalen
  • Ken Ross
  • Martin McDonnell
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


Friction stir dovetailing (FSD) was used to join 0.5 in. (12.7 mm) AA7099 to 0.5 in. (12.7 mm) Ni-Cr-Mo steel in a lap configuration. Two new FSD approaches are reported that significantly reduce zinc embrittlement of Fe–Al intermetallic compounds (IMCs) which form during conventional friction stir welding (FSW). The first method uses the general FSD approach where a custom designed tool is employed to extrude the AA7099 into the pre-machined dovetail groove of underlying steel by forming mechanical interlocking and metallurgical bonding simultaneously. The second method uses a two-step approach where FSD of AA6061 is first used to form a silicon-rich Fe-Al IMC within the dovetail groove. AA7099 plate is then joined to the AA6061 within the dovetail using conventional FSW. A discussion of the new FSD technique, joint configurations, and process parameters are provided along with joint microstructural analyses and mechanical performance.


Friction stir dovetailing FSD AA7099 AA6061 Rolled homogenous armor Dissimilar metals 



This work was supported by the U.S. Army Tank Automotive Research, Development, and Engineering Center [Military Interdepartmental Purchase Request 10834736, 11008837, 11079043]. Pacific Northwest National Laboratory is operated by the Battelle Memorial Institute for the U.S. Department of Energy under contract DE-AC06-76LO1830. The authors would like to thank Mr. Jason Scheuring, Application Engineer at Kaiser Aluminum, for providing the AA7099 alloy.


  1. 1.
    Dilthey U, Stein L (2006) Multimaterial car body design: challenge for welding and joining. Sci Technol Weld Joining 11(2):135–142CrossRefGoogle Scholar
  2. 2.
    David E (2003) Materials for cryogenics applications. In: 12th international scientific conference on achievements in mechanical and materials engineering, AMME 2003Google Scholar
  3. 3.
    Polsen E, Krogsrud L, Carter R, Oberle W, Haines C, Littlefield A (2014) Lightweight Combat Vehicle S and T Campaign. In: US Army TARDEC/Ground System Survivability Warren United StatesGoogle Scholar
  4. 4.
    Siwowski T (2006) Aluminium bridges–past, present and future. Struct Eng Int 16(4):286–293CrossRefGoogle Scholar
  5. 5.
    Ebrahimian A, Kokabi A (2017) Friction stir soldering: a novel route to produce graphite-copper dissimilar joints. Mater Des 116:599–608CrossRefGoogle Scholar
  6. 6.
    Upadhyay P, Hovanski Y, Jana S, Fifield LS (2017) Joining dissimilar materials using friction stir scribe technique. J Manuf Sci Eng 139(3):034501CrossRefGoogle Scholar
  7. 7.
    Zheng Q, Feng X, Shen Y, Huang G, Zhao P (2016) Dissimilar friction stir welding of 6061 Al to 316 stainless steel using Zn as a filler metal. J Alloy Compd 686:693–701CrossRefGoogle Scholar
  8. 8.
    Geiger M, Micari F, Merklein M, Fratini L, Contorno D, Giera A, Staud D (2008) Friction stir knead welding of steel aluminium butt joints. Int J Mach Tools Manuf 48(5):515–521CrossRefGoogle Scholar
  9. 9.
    Evans WT, Gibson BT, Reynolds JT, Strauss AM, Cook GE (2015) Friction stir extrusion: a new process for joining dissimilar materials. Manuf Lett 5:25–28CrossRefGoogle Scholar
  10. 10.
    Reza-E-Rabby M, Ross K, Overman NR, Olszta MJ, McDonnell M, Whalen SA (2018) Joining thick section aluminum to steel with suppressed FeAl intermetallic formation via friction stir dovetailing. Scr Mater 148:63–67CrossRefGoogle Scholar
  11. 11.
    Patterson EE, Hovanski Y, Field DP (2016) Microstructural characterization of friction stir welded aluminum-steel joints. Metall Mater Trans A 47(6):2815–2829CrossRefGoogle Scholar
  12. 12.
    Ratanathavorn W, Melander A, Magnusson H (2016) Intermetallic compounds in friction stirred lap joints between AA5754/galvanised ultra-high strength steel. Sci Technol Weld Joining 21(8):653–659CrossRefGoogle Scholar
  13. 13.
    Tanaka T, Morishige T, Hirata T (2009) Comprehensive analysis of joint strength for dissimilar friction stir welds of mild steel to aluminum alloys. Scr Mater 61(7):756–759CrossRefGoogle Scholar
  14. 14.
    Reza-E-Rabby M, Ross K, Whalen S, Hovanski Y, McDonnell M (2017) Solid-state joining of thick-section dissimilar materials using a new friction stir dovetailing (FSD) process. In: Friction stir welding and processing IX, pp 67–77. SpringerGoogle Scholar
  15. 15.
    Ross K, Sorensen C (2013) Advances in temperature control for FSP. In: Friction stir welding and processing VII, pp 301–310. SpringerGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Md. Reza-E-Rabby
    • 1
    • 2
    Email author
  • Scott Whalen
    • 1
  • Ken Ross
    • 1
  • Martin McDonnell
    • 3
  1. 1.Pacific Northwest National Laboratory, Applied Materials and Performance GroupRichlandUSA
  2. 2.Pacific Northwest National LaboratoryRichlandUSA
  3. 3.U.S. Army Tank Automotive ResearchDevelopment and Engineering CenterWarrenUSA

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