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Effect of B Addition on Thermal Stability of Lamellar Structure in Ti-47Al-2Cr-2Nb Alloys

Published online by Cambridge University Press:  26 February 2011

Y. Yamamoto ,
N. D. Evans ,
P. J. Maziasz  and
C. T. Liu
Y. Yamamoto
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN37831, U.S.A
N. D. Evans
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN37831, U.S.A
P. J. Maziasz
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN37831, U.S.A
C. T. Liu
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN37831, U.S.A
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Abstract

Thermal stability of fully lamellar microstructures in Ti-47Al-2Cr-2Nb (at.%) alloys with and without B additions has been evaluated in the temperature range of 800 to 1200°C. The alloy with 0.15B exhibits an α2 + γ fully lamellar microstructure containing ribbon-like structures (TiB2+β) inside the lamellar colonies. During aging at 800 and 1000°C, β particles surrounded by γ grains form adjacent to the ribbon-like structures. The formation of these grains is attributed to the precipitation of thin plate-like β phase along {1100} within the TiB2 ribbon particles, resulting in the loss of α2 plates around the ribbon-like structure by scavenging Ti. This allows coarsening γ lamellar plates to form new γ grains, and then the ribbon-like structure completely dissolves to leave only β particles. At 1200°C, discontinuous coarsening (DC) of the lamellae becomes the dominant mode of microstructural change for all the alloys. However, the ribbon-like structures in the alloy with B additions play a role in pinning the DC cells, which leads to higher thermal stability of the lamellar microstructure in that alloy.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 842: Symposium S – Integrative and Interdisciplinary Aspects of Intermetallics , 2004 , S6.8
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1. Kim, Y. W., in Gamma Titanium Aluminide, edited by Kim, Y. W., Wagnerand, R., Yamaguchi, M., (Warrendale, PA, TMS, 1995) 637.Google Scholar
2. Liu, C. T., Maziasz, P. J., Intermetallics, 6, 653 (1998).Google Scholar
3. Liu, C. T., Maziasz, P. J., Clemens, D. R., Schneibel, J. H., Sikka, V. K., Nieh, T. G., Wright, J. L., Walker, L. R., in Gamma Titanium Aluminide, edited by Kim, Y. W., Wagnerand, R., Yamaguchi, M., (Warrendale, PA, TMS, 1995), 679.Google Scholar
4. Maziasz, P. J., Liu, C. T., Metall. Mater. Trans. 29A, 105 (1998).Google Scholar
5. Maziasz, P. J., Liu, C. T., Mat. Res. Soc. Symp. Proc. 460, 219 (1997)Google Scholar
6. Liu, C. T., Schneibel, J. H., Maziasz, P. J., Wright, J. L., Easton, D. S., Intermetallics, 4, 429.Google Scholar
7. Maziasz, P. J., Ramanujan, R. V., Liu, C. T., Intermetallics, 5, 83 (1997).Google Scholar
8. Liu, C. T., unpublished work (1998).Google Scholar
9. Godfrey, A. B., Loretto, M. H., Intermetallics, 4, 47 (1996).Google Scholar
10. Schwartz, D. S., Shih, D. S., Mat. Res. Soc. Symp. Proc. 364, 787 (1995)Google Scholar
11. Yamamoto, Y., Maziasz, P. J., Liu, C. T., to be submitted (2004).Google Scholar
12. Yamamoto, Y., Takeyama, M., Matsuo, T. in Structural Intermetallics 2001, edited by Hemker, K. J., Dimiduk, D. M., Clemens, H., Darolia, R., Inui, H., Larson, J. M., Sikka, V. K., Thomas, M. and Wittenberger, J. D., (Warrendale, PA, TMS, 2001), 601.Google Scholar
13. Kobayashi, S., Ph. D. Thesis, Tokyo Institute of Technology (2001).Google Scholar