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Low-temperature superplasticity of ultra-fine-grained Ti-6Al-4V processed by equal-channel angular pressing

  • Y. G. Ko
  • C. S. Lee
  • D. H. Shin
  • S. L. Semiatin
Article

Abstract

The low-temperature superplasticity of ultra-fine-grained (UFG) Ti-6Al-4V was established as a function of temperature and strain rate. The equiaxed-alpha grain size of the starting material was reduced from 11 to 0.3 µm (without a change in volume fraction) by imposing an effective strain of ∼4 via isothermal, equal-channel angular pressing (ECAP) at 873 K. The ultrafine microstructure so produced was relatively stable during annealing at temperatures up to 873 K. Uniaxial tension and load-relaxation tests were conducted for both the starting (coarse-grained (CG)) and UFG materials at temperatures of 873 to 973 K and strain rates of 5 × 10−5 to 10−2 s−1. The tension tests revealed that the UFG structure exhibited considerably higher elongations compared to those of the CG specimens at the same temperature and strain rate. A total elongation of 474 pct was obtained for the UFG alloy at 973 K and 10−4 s−1. This fact strongly indicated that low-temperature superplasticity could be achieved using an UFG structure through an enhancement of grain-boundary sliding in addition to strain hardening. The deformation mechanisms underlying the low-temperature superplasticity of UFG Ti-6Al-4V were also elucidated by the load-relaxation tests and accompanying interpretation based on inelastic deformation theory.

Keywords

Material Transaction Total Elongation ECAP Pass Superplastic Defor 
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.

References

  1. 1.
    R. Boyer, G. Welsch, and E.W. Collings: Materials Properties Handbook: Titanium Alloys, ASM INTERNATIONAL. Materials Park, OH, 1994, pp. 483–636.Google Scholar
  2. 2.
    J.W. Edington, K.N. Melton, and C.P. Cutler: Progr. Mater. Sci., 1976, vol. 21, pp. 63–170.CrossRefGoogle Scholar
  3. 3.
    M. Meier and A.K. Mukherjee: Proc. 119th Annual Meeting of the Shaping and Forming Committee, T.R. McNelly and H.C. Heikkenen, eds., TMS, Warrendale, PA, 1990, pp. 317–32.Google Scholar
  4. 4.
    R.Z. Valiev, R.K. Islamgaliev, and I.V. Alexandrov: Progr. Mater. Sci., 2000, vol. 45, pp. 103–89.CrossRefGoogle Scholar
  5. 5.
    R.S. Mishra, V.V. Stolyarov, C. Echer, R.Z. Valiev, and A.K. Mukherjee: Mater. Sci. Eng., 2001, vol. A298, pp. 44–50.Google Scholar
  6. 6.
    A.V. Sergueeva, V.V. Stolyarov, R.Z. Valiev, and A.K. Mukherjee: Scripta Mater., 2000, vol. 43, pp. 819–24.CrossRefGoogle Scholar
  7. 7.
    A.V. Sergueeva, V.V. Stolyarov, R.Z. Valiev, and A.K. Mukherjee: Mater. Sci. Eng., 2002, vol. A323, pp. 318–25.Google Scholar
  8. 8.
    G.A. Salishchev, R.M. Galeyev, O.R. Valiakhmetov, R.V. Safiullin, R.Y. Lutfullin, O.N. Senkov, F.H. Froes, and O.A. Kaibyshev: J. Mater. Proc. Technol., 2001, vol. 116, pp. 265–68.CrossRefGoogle Scholar
  9. 9.
    S.N. Patankar, J.P. Escobedo, D.P. Field, G. Salishchev, R.M. Galeyev, O.R. Valiakhmetov, and F.H. Froes: J. Alloys Compounds, 2002, vol. 345, pp. 221–27.CrossRefGoogle Scholar
  10. 10.
    V.M. Segal: Mater. Sci. Eng. A, 1999, vol. A271, pp. 322–33.Google Scholar
  11. 11.
    S. Komura, Z. Horita, M. Furukawa, M. Nemoto, and T.G. Langdon: Metall. Mater. Trans. A, 2001, vol. 32A, pp. 707–16.CrossRefGoogle Scholar
  12. 12.
    D.H. Shin, B.C. Kim, Y.-S. Kim, and K.-T. Park: Acta Mater., 2000, vol. 48, pp. 2247–55.CrossRefGoogle Scholar
  13. 13.
    D.P. DeLo and S.L. Semiatin: Metall. Mater. Trans. A, 1999, vol. 30A, pp. 2473–81.CrossRefGoogle Scholar
  14. 14.
    Y.G. Ko, W.S. Jung, D.H. Shin, and C.S. Lee: Scripta Mater., 2003, vol. 48, pp. 197–202.CrossRefGoogle Scholar
  15. 15.
    L. Lin, Z. Liu, L. Chen, T. Liu, and S. Wu: Met. Mater. Int., 2004, vol. 10, pp. 501–06.Google Scholar
  16. 16.
    D. Lee and E.W. Hart: Metall. Trans. A, 1971, vol. 2A, pp. 1245–48.Google Scholar
  17. 17.
    P.G. Partridge: Metall. Rev., 1968, vol. 12, pp. 169–94.Google Scholar
  18. 18.
    K.-T. Park, D.-Y. Hwang, S.-Y. Chang, and D.H. Shin: Metall. Mater. Trans. A, 2002, vol. 33A, pp. 2859–67.CrossRefGoogle Scholar
  19. 19.
    S.L. Semiatin and J.J. Jonas: Formability and Workability of Metals: Plastic Instability and Flow Localization, ASM, Metals Park, OH, 1984, pp. 149–98.Google Scholar
  20. 20.
    Y.W. Chang and E.C. Aifantis: Proc. 2nd Int. Conf. on Constitutive Laws for Engineering Materials—Theory and Applications, Tuscon, AZ, 1987, C.S. Desai, ed., pp. 293–300.Google Scholar
  21. 21.
    T.K. Ha and Y.W. Chang: Acta Mater., 1998, vol. 46, pp. 2741–49.CrossRefGoogle Scholar
  22. 22.
    I.I. Novikov, V.K. Portnoy, and V.S. Levchenko: Acta Mater., 1981, vol. 29, pp. 1077–90.CrossRefGoogle Scholar
  23. 23.
    R.Z. Valiev and T.G. Langdon: Acta Mater., 1993, vol. 41, pp. 949–54.CrossRefGoogle Scholar
  24. 24.
    Y. N. Kwon and Y.W. Chang: Metall. Mater. Trans. A, 1999, vol. 30A. pp. 2037–47.CrossRefGoogle Scholar
  25. 25.
    J.S. Kim, Y.W. Chang, and C.S. Lee: Metall. Mater. Trans. A, 1998, vol. 29A, pp. 217–26.CrossRefGoogle Scholar
  26. 26.
    Y.G. Ko, W.G. Kim, C.S. Lee, and D.H. Shin: Mater. Sci. Eng. A, 2005, vols. 410–411, pp. 156–59.Google Scholar
  27. 27.
    F.A. Mohamed and T.G. Langdon: Phys. Status Solidi, 1976, vol. 33, pp. 375–81.CrossRefGoogle Scholar
  28. 28.
    A. Arieli and A. Rosen: Metall. Trans. A, 1977, vol. 8A, pp. 1591–96.Google Scholar
  29. 29.
    Z.X. Guo and N. Ridley: Mater. Sci. Technol., 1987, vol. 3, pp. 945–53.Google Scholar
  30. 30.
    L. Briottet, J.J. Jonas, and F. Montheillet: Acta Mater., 1996, vol. 44, pp. 1665–72.CrossRefGoogle Scholar
  31. 31.
    T. Seshacharyulu, S.C. Medeiros, W.G. Frazier, and Y.V.R.K. Prasad: Mater. Sci. Eng. A, 2000, vol. A284, pp. 184–94.Google Scholar
  32. 32.
    Y. Mishin and Ch. Herzig: Acta Mater., 2000, vol. 48, pp. 589–623.CrossRefGoogle Scholar
  33. 33.
    T.G. Langdon: Mater. Sci. Eng. A, 1994, vol. A174, pp. 225–30.Google Scholar
  34. 34.
    R.Z. Valiev and O.A. Kaibyshev: Acta Mater., 1983, vol. 31, pp. 2121–28.CrossRefGoogle Scholar
  35. 35.
    J.S. Kim: Ph.D. Thesis, POSTECH, Korea, 1999.Google Scholar
  36. 36.
    M. Kawazoe, T. Shibata, T. Mukai, and K. Higashi: Scripta Mater., 1997, vol. 36, pp. 699–705.CrossRefGoogle Scholar
  37. 37.
    S.H. Yu, Y.B. Chun, W.Q. Cao, M.H. Kim, S.W. Chae, S.I. Kwun, D.H. Shin, and S.K. Hwang: Met. Mater. Int., 2005, vol. 11, pp. 101–11.CrossRefGoogle Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2006

Authors and Affiliations

  • Y. G. Ko
    • 1
  • C. S. Lee
    • 1
  • D. H. Shin
    • 2
  • S. L. Semiatin
    • 3
  1. 1.the Department of Materials Science and EngineeringPohang University of Science and TechnologyPohangKorea
  2. 2.the Department of Metallurgy and Materials ScienceHanyang UniversityGyeonggi-DoKorea
  3. 3.the Air Force Research LaboratoryAFRL/MLLMWright-Patterson AFB

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