High-temperature deformation behavior of a gamma TiAl alloy—Microstructural evolution and mechanisms

  • Jeoung Han Kim
  • Young Won Chang
  • Chong Soo Lee
  • Tae Kwon Ha


The present investigation was carried out in the context of the internal-variable theory of inelastic deformation and the dynamic-materials model (DMM), to shed light on the high-temperature deformation mechanisms in TiAl. A series of load-relaxation tests and tensile tests were conducted on a fine-grained duplex gamma TiAl alloy at temperatures ranging from 800 °C to 1050 °C. Results of the load-relaxation tests, in which the deformation took place at an infinitesimal level (ε ≅ 0.05), showed that the deformation behavior of the alloy was well described by the sum of dislocation-glide and dislocation-climb processes. To investigate the deformation behavior of the fine-grained duplex gamma TiAl alloy at a finite strain level, processing maps were constructed on the basis of a DMM. For this purpose, compression tests were carried out at temperatures ranging from 800 °C to 1250 °C using strain rates ranging from 10 to 10−4/s. Two domains were identified and characterized in the processing maps obtained at finite strain levels (0.2 and 0.6). One domain was found in the region of 980 °C and 10−3/s with a peak efficiency (maximum efficiency of power dissipation) of 48 pct and was identified as a domain of dynamic recrystallization (DRx) from microstructural observations. Another domain with a peak efficiency of 64 pct was located in the region of 1250 °C and 10−4/s and was considered to be a domain of superplasticity.


Material Transaction Power Dissipation Inelastic Deformation Intergranular Crack TiAl Alloy 


  1. 1.
    Y.-W. Kim: J. Met., 1995, vol. 47, pp. 39–41.Google Scholar
  2. 2.
    R.W. Hayes and B. London: Acta Metall., 1992, vol. 40, p. 2167.CrossRefGoogle Scholar
  3. 3.
    P.L. Martin, M.G. Mendiratta, and H.A. Lipsitt: Metall. Trans. A, 1983, vol. 14A, p. 2170.Google Scholar
  4. 4.
    Y.-W. Kim and F.H. Froes: in High Temperature Aluminides and Intermetallics, S.H. Wang et al., eds., TMS, Warrendale, PA, 1990, pp. 465–92.Google Scholar
  5. 5.
    S.C. Huang and E.L. Hall: Metall. Trans. A, 1991, vol. 22A, p.427.Google Scholar
  6. 6.
    S.L. Semiatin, D.C. Vollmer, S. El-Soudani, and C. Su: Scripta Metall. Mater., 1991, vol. 25, p. 1409.CrossRefGoogle Scholar
  7. 7.
    H.E. Deve, A.G. Evans, and D.S. Shih: Acta Metall. Mater., 1992, vol. 40, p. 1259.CrossRefGoogle Scholar
  8. 8.
    T. Kawabata, T. Kanai, and O. Izumi: Acta Metall. Mater., 1985, vol. 33, pp. 1355–66.CrossRefGoogle Scholar
  9. 9.
    M. Nobuki and T. Tsujimoto: Iron Steel Inst. Jpn. Int. 31 (1991), pp. 931–937.Google Scholar
  10. 10.
    T.K. Ha and Y.W. Chang: Acta Mater. 1998, vol. 46, p. 2741.CrossRefGoogle Scholar
  11. 11.
    Y.V.R.K. Prasad and S. Sasidhara: Hot Working Guide—A Compendium of Processing Maps, ASM INTERNATIONAL, Materials Park, OH, 1997.Google Scholar
  12. 12.
    J.S. Kim, Y.W. Chang, and C.S. Lee: Metall. Mater. Trans. A, 1998, vol. 29A, p. 217.CrossRefGoogle Scholar
  13. 13.
    J.S. Kim, W.J. Nam, and C.S. Lee: Met. Mater., 1998, vol. 4, p. 1041.CrossRefGoogle Scholar
  14. 14.
    D. Lee and E.W. Hart: Metall. Trans., 1971, vol. 2, pp. 1245–48.Google Scholar
  15. 15.
    T.K. Ha, H.J. Sung, K.S. Kim, and Y.W. Chang: Mater. Sci. Eng. 1999, vol. 271, p. 166.Google Scholar
  16. 16.
    F. Appel, U. Lorenz, M. Oehring, U. Sparka, and R. Wagner: Mater. Sci. Eng. A, 1997, vol. 233 (1–2).CrossRefGoogle Scholar
  17. 17.
    W.J. Zhang, Z.C.C. Liu, G.L. Chen, and Y.-W. Kim: Mater. Sci. Eng., 1999, vol. A271, pp. 416–23.Google Scholar
  18. 18.
    T.K. Ha and Y.W. Chang: Scripta Mater., 1996, vol. 35, p. 1317.CrossRefGoogle Scholar
  19. 19.
    J.S. Kim, J.H. Kim, Y.T. Lee, C.G. Park, and C.S. Lee: Mater. Sci. Eng. A, 1999, vol. A263, pp. 272–80.Google Scholar
  20. 20.
    V. Seetharaman and C.M. Lombard: in Microstructure/Property Relationships in Titanium Aluminides and Alloys, Y.-W. Kim and R.R. Boyer, eds., TMS, (Warrendale, PA, 1991), pp. 237–51.Google Scholar
  21. 21.
    H. Ziegler: in Progress in Solid Mechanics, I.N. Sneddon and R. Hill, eds., Wiley, New York, NY, 1965, vol. 4, pp. 91–193.Google Scholar
  22. 22.
    N. Ravichandran and Y.V.R.K. Prasad: Mater. Sci. Eng., 1992, vol. A156, p. 195.Google Scholar
  23. 23.
    N. Srinivasan and Y.V.R.K. Prasad: Mater. Sci. Technol., 1992, vol. 9, p. 206.Google Scholar
  24. 24.
    O. Sivakesavam, I.S. Rao, and Y.V.R.K. Prasad: Mater. Sci. Technol., 1993, vol. 9, p. 805.Google Scholar
  25. 25.
    J.K. Chakravarty, Y.V.R.K. Prasad, and M.K. Asundi: Metall. Trans. A, 1991, vol. 22A, pp. 829–36.Google Scholar
  26. 26.
    J.A. Bailey and A.R.E. Singer: J. Inst. Met., 1963–64, vol. 92, p. 404.Google Scholar
  27. 27.
    N. Ravichandran and Y.V.R.K. Prasad: Metall. Trans. A, 1991, vol. 22A, pp. 2339–48.Google Scholar
  28. 28.
    G. Hug, A. Loiseau, and P. Veyssiere: Phil. Mag., 1988, vol. 57, p. 499.Google Scholar
  29. 29.
    J. Panova and D. Farkas: in Gamma Titanium Aluminides, Y.-W. Kim, R. Wagner, and M. Yamaguchi, eds., TMS, Warrendale, PA, 1995, pp. 331–38.Google Scholar
  30. 30.
    D.G. Morris, S. Gunter, and M. Leboeuf: Phil. Mag. A, 1994, vol. 69, p. 527.Google Scholar
  31. 31.
    P.K. Sagar and Y.V.R.K. Prasad: Z. Metall., 1998, vol. 89 (6), pp. 433–41.Google Scholar
  32. 32.
    C.M. Sabinash, S.M.L. Sastry, and K.L. Jerina: Mater. Sci. Eng. A, 1995, vols. A192–A193, pp. 837–47.Google Scholar
  33. 33.
    N. Fujitsuna, H. Ohyama, Y. Miyamoto, and Y. Ashida: Iron Steel Inst. Jpn. Int., 1991, vol. 31 (10), pp. 1147–53.Google Scholar
  34. 34.
    M.A. Morris and M. Leboeuf: Intermetallics, 1997, vol. 5, pp. 339–54.CrossRefGoogle Scholar
  35. 35.
    W.B. Lee, H.S. Yang, Y.-W. Kim, and A.K. Mukherjee: Scripta Metall., 1993, vol. 29, pp. 1403–08.CrossRefGoogle Scholar
  36. 36.
    Y.V.R.K. Prasad and T. Seshacharyulu: Int. Mater. Rev., 1988, vol. 43 (6), pp. 244–58.Google Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2003

Authors and Affiliations

  • Jeoung Han Kim
    • 1
  • Young Won Chang
    • 1
  • Chong Soo Lee
    • 1
  • Tae Kwon Ha
    • 2
  1. 1.the Center for Advanced Aerospace Materials and the Department of Materials Science and EngineeringPohang University of Science and TechnologyPohangKorea
  2. 2.the Research Institute of Industrial Science and TechnologyPohangKorea

Personalised recommendations