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Microstructure of Massively Transformed γ-TiAl Phase Studied by High-Resolution Electron Microscopy

Published online by Cambridge University Press:  15 February 2011

E. Abe ,
T. Kumagai ,
S. Kajiwara  and
M. Nakamura
E. Abe
Affiliation:
National Research Institute for Metals, Sengen, Tsukuba 305, Japan, abe@tamamori.nrim.go.jp
T. Kumagai
Affiliation:
National Research Institute for Metals, Sengen, Tsukuba 305, Japan, abe@tamamori.nrim.go.jp
S. Kajiwara
Affiliation:
National Research Institute for Metals, Sengen, Tsukuba 305, Japan, abe@tamamori.nrim.go.jp
M. Nakamura
Affiliation:
National Research Institute for Metals, Sengen, Tsukuba 305, Japan, abe@tamamori.nrim.go.jp
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Abstract

A microstructure of the massively transformed γ-TiAl (γm) phase in a Ti-48at.%Al alloy, which was heat treated in the high-temperature α-Ti (disordered hep) single phase field (1683K), followed by ice water quenching, has been examined using high-resolution electron microscopy. The characteristic features of the microstructure originated from the α→γ massive transformation have been clarified in detail, which are as follows. (1) Extremely thin hep plates (about 0.8–2nm in thickness), which are considered to be a retained α phase, are found to exist in the γm phase. (2) Twin boundaries are found to be not flat interfaces, that is, twin interfaces are not on the exact (111) mirror plane. This situation is attributed to the existence of a number of partial dislocations at the twin boundaries. (3) Antiphase relationship between the regions either side of the thin rotated domain wall [1] is confirmed. The validity of this situation is explained by assuming that the thin rotated domain wall has been grown from a simple antiphase domain boundary. On the basis of these facts, mechanism of the α→γ massive transformation has been discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 201
Copyright
Copyright © Materials Research Society 1997

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References

REFERENCES

1. Zhang, X. D. and Loretto, M. H., Phil. Mag. A, 71, 421 (1995).Google Scholar
2. Wang, P., Viswanathan, G. B. and Vasudevan, V. K., Metall. Trans. A, 23A, 690 (1992).Google Scholar
3. Jones, S. A. and Kaufman, M. J., Acta Metall. Mater., 41, 387 (1993).Google Scholar
4. Takeyama, M., Kumagai, T., Nakamura, M. and Kikuchi, M., in Structural Intermetallics. edited by Darolia, R. et al. (TMS Proc, Warrendale, PA, 1993) pp. 167–176.Google Scholar
5. Plichta, M. R., Clark, W. A. T. and Aaronson, H. I., Metall. Trans. A, 15A, 427 (1984).Google Scholar
6. Li, Y. G. and Loretto, M. H., Acta Metall. Mater., 41, 3413 (1993).Google Scholar
7. Denquin, A. and Naka, S., Phil. Mag. Lett., 68, 13 (1993).Google Scholar
8. Kumagai, T., Abe, E., Takeyama, M. and Nakamura, M., in High-Temperature Ordered Intermetallic alloys VI. edited by Horton, J. A. et al. (MRS Proc. 364, Pittsburgh, PA, 1995) pp. 181–186.Google Scholar
9. Kumagai, T., Abe, E., Takeyama, M. and Nakamura, M., Scripta Mater., in press.Google Scholar
10. Zhang, X. D. and Loretto, M. H., in High-Temperature Ordered Intermetallic alloys VI. edited by Horton, J. A. et al. (MRS Proc. 364, Pittsburgh, PA, 1995) pp. 611–616.Google Scholar
11. Abe, E., Kajiwara, S., Kumagai, T. and Nakamura, M., Phil. Mag. A, in press.Google Scholar
12. Abe, E., Kumagai, T. and Nakamura, M., Phil. Mag. Lett., 72, 291 (1995).Google Scholar
13. Abe, E., Kumagai, T. and Nakamura, M., in Metastable Phases and Microstrucutres. edited by Bormann, R. et al. (MRS Proc. 400, Pittsburgh, PA, 1995) pp. 281–286.Google Scholar
14. Singh, S. R. and Howe, J.M., Phil. Mag. Lett, 65, 233 (1992).Google Scholar
15. Appel, F., Beaven, P. A. and Wagner, R., Acta Metall. Mater., 41, 1721 (1993).Google Scholar
16. Abe, E., Kumagai, T., Kajiwara, S. and Nakamura, M., Mater. Trans. JIM, in press.Google Scholar
17. Abe, E. and Nakamura, M., Phil. Mag. Lett., in press.Google Scholar
18. Foo, C. L. and Yoo, M. H., Phil. Mag. Lett., 62, 159 (1990).Google Scholar
19. Zhang, X. D., Li, Y. G., Kaufman, M. J. and Loretto, M. H., Acta Mater., 44, 3735 (1996).Google Scholar