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Effect of Preoxidation and Grain Size on Ductility of a Boron-Doped Ni3Al at Elevated Temperatures

Published online by Cambridge University Press:  26 February 2011

M. Takeyama  and
C. T. Liu
M. Takeyama
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6115, U.S.A.
C. T. Liu
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6115, U.S.A.
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Abstract

The ductility of preoxidized Ni3Al (Ni-23Al-0.5Hf-0.2B, at.%) specimens with various grain sizes (17∼193 μm) was evaluated by means of tensile tests at 600 and 760°C in vacuum. It was found that the preoxidation does not affect the ductility of the finest-grained material at either temperature, whereas it causes severe embrittlement in the largest-grained material, especially at 760°C. A continuous, thin Al-rich oxide layer, which forms on the fine-grained samples, protects the underlying alloy from oxygen penetration, preventing any loss of ductility, whereas the nickel-rich oxide which forms on the large-grained samples allows oxygen to penetrate along grain boundaries, causing severe embrittlement. The grain boundaries act as short-circuit paths for rapid diffusion of aluminum atoms from the bulk to the surfaces, and this is responsible for the difference in oxidation behavior between fine- and large-grained materials. The embrittlement of large-grained samples can be eliminated through control of oxide formation on Ni3Al surfaces.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 133: Symposium H – High-Temperature Ordered Intermetallic Alloys III , 1988 , 293
Copyright
Copyright © Materials Research Society 1989

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References

REFERENCES

1. Liu, C. T., White, C. L. and Lee, E. H., Scripta Metall. 19, 1247 (1985).CrossRefGoogle Scholar
2. Liu, C. T. and White, C. L., Acta Metall. 35, 643 (1987).Google Scholar
3. Taub, A. I., Chang, K. -M. and Liu, C. T., Scripta Metall. 20, 1618 (1986).Google Scholar
4. Takeyama, M. and Liu, C. T., Acta Metall. 36, 1241 (1988).CrossRefGoogle Scholar
5. Weihs, T. P., Zinoviev, V., Viens, D. V. and Schulson, E. M., Acta Metall. 35, 1109 (1987).CrossRefGoogle Scholar
6. Choudhury, A., White, C. L. and Brooks, C. R., Scripta Metall. 20, 1061 (1986).CrossRefGoogle Scholar
7. Davis, L. E., MacDonald, N. C., Palmberg, P. W., Riach, G. E. and Weber, R. E., Handbook of Auger Electron Spectroscopy, Perkin-Elmer Corporation, Eden Prairie, Minn (1978).Google Scholar
8. Takeyama, M. and Liu, C. T., unpublished results, Oak Ridge National Laboratory (1988).Google Scholar
9. Giggins, C. S. and Pettit, F. S., TMS-AIME 245, 2509 (1969).Google Scholar
10. Yurek, G. J., Eisen, D. and Garratt-Reed, A., Metall. Trans. A 13A, 473 (1982).CrossRefGoogle Scholar
11. Pettit, F. S., TMS-AIME 239, 1296 (1967).Google Scholar