Korean Journal of Metals and Materials (대한금속재료학회지)

The Korean Institute of Metals and Materials (대한금속재료학회)
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A Study on the Creep Strength of L12 and B2-ordered Intermetallics

  • Han, Seung-Oh (Institute of Fusion Technology, Hoseo University) ;
  • Han, Chang-Suk (Dept. of Defense Science & Technology, Hoseo University)
  • Received : 2010.09.09
  • Published : 2010.12.25
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Abstract

The creep rates of polycrystalline $L1_2$-ordered $Co_3Ti$ and B2-ordered NiAl-Hf intermetallics decrease appreciably with the fine precipitation of the coherent disordered fcc Co-rich phase and $Ni_2AlHf$ phase. With B2-ordered NiAl containing $L2_1-Ni_2AlHf$ precipitates, transmission electron microscope observations of the interaction between dislocations and spherical precipitates revealed that the dislocations tend to be strongly attracted to the particle interfaces during the creep deformation. On the other hand, with $L1_2$-ordered $Co_3Ti$, the significance of the threshold stress is discussed based upon the transmission electron microscope observations of the interaction between dislocations and precipitates. The superdislocations produced during deformation tend to be strongly attracted and dissociated as they meet the coherent disordered precipitates because the anti-phase boundary energy in the disordered phase was zero. An extra force required to pull the dislocations out of the disordered particles during the creep deformation establishes the threshold stress which is beneficial for improving creep strength under lower stresses.

Keywords

Acknowledgement

Supported by : Hoseo University

References

  1. D. M. Sha and D. N. Duhl, High Temperature Ordered Intermetallic Alloys II, Mat. Res. Soc. Symp. Proc. 81, 411 (1987).
  2. H. J. Jun, C. G. Park, and Y. W. Chang, J. Kor. Inst. Met. & Mater. 38, 1019 (2000).
  3. M. V. Nathal, Ordered Intermetallics-Physical Metallurgy and Mechanical Behavior, NATO ASI Series E, 213, 541 (1992).
  4. T. Khan, P. Caron, and S. Naka, High Temperature Aluminides and Intermetallics, TMS, 219 (1990).
  5. S. H. Song, K. Kishida, M. Demura, M. C. Kim, M. H. Oh, T. Hirano, and D. M. Wee, J. Kor. Inst. Met. & Mater. 44, 10 (2006).
  6. J. H. Schneibel and P. M. Hazzledine, Ordered Intermetallics-Physical Metallurgy and Mechanical Behaviour, NATO ASI Series E 213, 565 (1992).
  7. T. Takasugi and O. Izumi, Acta Met. 33, 39 (1985). https://doi.org/10.1016/0001-6160(85)90217-2
  8. D. H. Sastry and R. S. Sunder, Proc. of the Int. Symp. on Nickel and Iron Aluminides, ASM, 123 (1996).
  9. R. Darolia, J. Met. 43, 44 (1991).
  10. R. Darolia, Structural Intermetallics, MMS, 495 (1993).
  11. W. S. Walson, R. D. Field, J. R. Dobbs, D. F. Lahrman, and R. Darolia, Structural Intermetallics, MMS, 523 (1993).
  12. M. Takeyama and C. T. Liu, J. Mater. Res. 5, 1189 (1990). https://doi.org/10.1557/JMR.1990.1189
  13. A. Garg, S. V. Raj, and R. Darolia, Micromechnics of Advanced Materials 255 (1993).
  14. A. Garg, R. D. Nobe, and R. Darolia, Acta Metall. Mater. 44, 2809 (1996). https://doi.org/10.1016/1359-6454(95)00374-6
  15. H. Nakajima, T. Nakamura, M. Koiwa, T. Takasugi, and O. Izumi, Scr. Metall. 22, 507 (1988). https://doi.org/10.1016/0036-9748(88)90014-2
  16. J. C. Gibeling and W. D. Nix, Mater Sci. Eng. 45, 123 (1980). https://doi.org/10.1016/0025-5416(80)90218-9
  17. R. L. Coble, J. Appl. Phys. 34, 1679 (1963). https://doi.org/10.1063/1.1702656
  18. F. A. Mohamed and T. G. Langdon, Acta Metall. 22, 779 (1974). https://doi.org/10.1016/0001-6160(74)90088-1
  19. J. Weetman, J. Appl. Phys. 28, 362 (1957). https://doi.org/10.1063/1.1722747
  20. S. L. Robinson and O. D. Sherby, Acta Metall. 24, 399 (1976). https://doi.org/10.1016/0001-6160(76)90060-2
  21. G. Gonzalez-Doncel and O. D. Sherby, Acta Metall. Mater. 41, 2797 (1993). https://doi.org/10.1016/0956-7151(93)90094-9
  22. D. B. Miracle, Acta Metall. Mater. 41, 649 (1993). https://doi.org/10.1016/0956-7151(93)90001-9
  23. S. V. Raj and S. C. Farmer, Metall. Mater. Trans. 26A, 343 (1995).
  24. J. Rosler and E. Arzt, Acta Metall. Mater. 38, 671 (1990). https://doi.org/10.1016/0956-7151(90)90223-4