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Metallurgical and Materials Transactions A

, Volume 32, Issue 12, pp 3033–3042 | Cite as

Microstructural factors governing hardness in friction-stir welds of solid-solution-hardened Al alloys

  • Yutaka S. Sato
  • Seung Hwan C. Park
  • Hiroyuki Kokawa
Article

Abstract

Microstructural factors governing hardness in friction-stir welds of the solid-solution-hardened Al alloys 1080 and 5083 were examined by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The effect of grain boundary on the hardness was examined in an Al alloy 1080 which did not contain any second-phase particles. The weld of Al alloy 1080 had a slightly greater hardness in the stir zone than the base material. The maximum hardness was located in the thermomechanically affected zone (TMAZ). The stir zone consisted of recrystallized fine grains, while the TMAZ had a recovered grain structure. The increase in hardness in the stir zone can be explained by the Hall-Petch relationship. On the other hand, the hardness profiles in the weld of Al alloy 5083 were roughly homogeneous. Friction-stir welding created the fine recrystallized grains in the stir zone and recovered grains in the TMAZ in the weld of this alloy. The stir zone and the TMAZ had slightly higher dislocation densities than the base material. Many small Al6(Mn,Fe) particles were detected in all the grains of the weld. The hardness profiles could not be explained by the Hall-Petch relationship, but rather by Orowan hardening. The results of the present study suggest that the hardness profile is mainly affected by the distribution of small particles in friction-stir welds of Al alloys containing many such particles.

Keywords

Welding Material Transaction Hardness Profile Welding Direction Subgrain Structure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    C.J. Dawes: Proc. 6th Int. Symp. of JWS, JWS, Nagoya, Japan, 1996, pp. 711–17.Google Scholar
  2. 2.
    G. Liu, L.E. Murr, C.-S. Niou, J.C. McClure, and F.R. Vega: Scripta Mater., 1997, vol. 37, pp. 355–61.CrossRefGoogle Scholar
  3. 3.
    L.E. Murr, G. Liu, and J.C. McClure: J. Mater. Sci., 1998, vol. 33, pp. 1243–51.CrossRefGoogle Scholar
  4. 4.
    Y. Li, L.E. Murr, and J.C. McClure: Mater. Sci. Eng. A, 1999, vol. 271, pp. 213–23.CrossRefGoogle Scholar
  5. 5.
    O.T. Midling: Proc. ICAA-4, Atlanta, GA, 1994, pp. 451–58.Google Scholar
  6. 6.
    S. Benavides, Y. Li, L.E. Murr, D. Brown, and J.C. McClure: Scripta Mater., 1999, vol. 41, pp. 809–15.CrossRefGoogle Scholar
  7. 7.
    Y.S. Sato, H. Kokawa, M. Enomoto, and S. Jogan: Metall. Mater. Trans. A, 1999, vol. 30A, pp. 2429–37.Google Scholar
  8. 8.
    Y.S. Sato, H. Kokawa, M. Enomoto, S. Jogan, and T. Hashimoto: Metall. Mater. Trans. A, 1999, vol. 30A, pp. 3125–30.Google Scholar
  9. 9.
    Y.S. Sato, H. Kokawa, K. Ikeda, M. Enomoto, S. Jogan, and T. Hashimoto: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 941–48.Google Scholar
  10. 10.
    M.W. Mahoney, C.G. Rhodes, J.G. Flintoff, R.A. Spurling, and W.H. Bingel: Metall. Mater. Trans. A, 1998, vol. 29A, pp. 1955–64.CrossRefGoogle Scholar
  11. 11.
    K.V. Jata, K.K. Sankaran, and J.J. Ruschau: Metall. Mater. Trans. A, 2000, vol. 31A, pp. 2181–92.Google Scholar
  12. 12.
    M. Kumagai and S. Tanaka: J. Light Met. Welding Constr., 2001, vol. 39, pp. 22–28.Google Scholar
  13. 13.
    A.P. Reynolds: Proc. 5th Int. Conf. on Trends in Welding Research, Pine Mountain, GA, 1998, ASM International, Materials Park, OH, 1999, pp. 563–67.Google Scholar
  14. 14.
    L.-E. Svensson, L. Karlsson, H. Larsson, B. Karlsson, M. Fazzini, and J. Karlsson: Sci. Technol. Weld. Joining, 2000, vol. 5, pp. 285–96.CrossRefGoogle Scholar
  15. 15.
    L.E. Murr, G. Liu, and J.C. McClure: J. Mater. Sci. Lett., 1997, vol. 16, pp. 1801–03.CrossRefGoogle Scholar
  16. 16.
    Y.S. Sato, M. Urata, H. Kokawa, K. Ikeda, and M. Enomoto: Scripta Mater., 2001, vol. 45, pp. 109–14.CrossRefGoogle Scholar
  17. 17.
    K. Kannan, C.H. Johnson, and C.H. Hamilton: Metall. Mater. Trans. A, 1998, vol. 29A, pp. 1211–20.Google Scholar
  18. 18.
    R.E. Sanders, Jr., S.F. Baumann, and H.C. Stumpf: in Treatise on Materials Science and Technology, vol. 31, Aluminum Alloys-Contemporary Research and Applications, A.K. Vasudevam and R.D. Doherty, eds., Academic Press, New York, NY, 1989, pp. 65–105.Google Scholar
  19. 19.
    J. Hu, K. Ikeda, and T. Murakami: J. Jpn Inst. Light Met., 1996, vol. 46, pp. 126–31.CrossRefGoogle Scholar
  20. 20.
    B.A. Parker: in Treatise on Materials Science and Technology, vol. 31, Aluminum Alloys—Contemporary Research and Applications, A.K. Vasudevam and R.D. Doherty, eds., Academic Press, New York, NY, 1989, pp. 539–62.Google Scholar
  21. 21.
    Y.S. Sato, M. Urata, H. Kokawa, and K. Ikeda: Proc. 7th Int. Symp. of JWS, JWS, Kobe, Japan, 2001, in press.Google Scholar
  22. 22.
    H. Fujita and T. Tabata: Acta Metall., 1973, vol. 21, pp. 355–65.CrossRefGoogle Scholar
  23. 23.
    N. Hansen: Acta Metall., 1977, vol. 25, pp. 862–69.Google Scholar
  24. 24.
    Y. Ito, N. Tsuji, Y. Saito, H. Utsunomiya, and T. Sakai: J. Jpn Inst. Met., 2000, vol. 64, pp. 429–37.Google Scholar
  25. 25.
    H. Hasegawa, S. Komura, A. Utsunomiya, Z. Horita, M. Furukawa, M. Nemoto, and T.G. Langdon: Mater. Sci. Eng. A, 1999, vol. A265, pp. 188–96.Google Scholar
  26. 26.
    M.F. Ashby and D.R.H. Jones: Engineering Materials I, Pergamon Press, Oxford, United Kingdom, 1980, p. 105.Google Scholar
  27. 27.
    K.V. Jata and S.L. Semiatin: Scripta Mater., 2001, vol. 43, pp. 743–49.Google Scholar
  28. 28.
    Y.S. Sato and H. Kokawa: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 3023–31.Google Scholar
  29. 29.
    C.G. Rhodes, M.W. Mahoney, W.H. Bingel, R.A. Spurling, and C.C. Bampton: Scripta Mater., 1997, vol. 36, pp. 69–75.CrossRefGoogle Scholar
  30. 30.
    R.S. Mishra, M.W. Mahoney, S.X. McFadden, N.A. Mara, and A.K. Mukherjee: Scripta Mater., 2000, vol. 42, pp. 163–68.Google Scholar
  31. 31.
    H. Okamura: J. Jpn Welding Soc., 2000, vol. 67, pp. 560–71.Google Scholar
  32. 32.
    H.B. McShane, C.P. Lee, and T. Sheppard: Mater. Sci. Technol., 1990, vol. 6, pp. 428–40.Google Scholar
  33. 33.
    Thermochemical Database for Light Metal Alloys, COST 507, I. Ansara, A.T. Dinsdale, and M.H. Rand, eds., European Commission, Luxembourg, 1998.Google Scholar
  34. 34.
    R. Armstrong, I. Godd, R.M. Douthwaite, and N.J. Petch: Phil. Mag., 1962, vol. 7, pp. 45–58.Google Scholar
  35. 35.
    J.D. Verhoeven: Fundamentals of Physical Metallurgy, John Wiley & Sons, New York, NY, 1975, pp. 118–20.Google Scholar
  36. 36.
    J.D. Verhoeven: Fundamentals of Physical Metallurgy, John Wiley & Sons, New York, NY, 1975, pp. 406–07.Google Scholar
  37. 37.
    M. Kato: Introduction of the Theory of Dislocations, Shokabo, Tokyo, 1999, pp. 123–24.Google Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2001

Authors and Affiliations

  • Yutaka S. Sato
    • 1
  • Seung Hwan C. Park
    • 1
  • Hiroyuki Kokawa
    • 1
  1. 1.Department of Materials Processing, Graduate School of EngineeringTohoku UniversitySendaiJapan

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