Hostname: page-component-8448b6f56d-tj2md Total loading time: 0 Render date: 2024-04-25T06:35:11.312Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystal structure of intermetallic phase in Fe–20Cr–4Al–0.5Y alloy by convergent beam electron diffraction

Published online by Cambridge University Press:  31 January 2011

Raghavan Ayer ,
J. C. Scanlon ,
T. A. Ramanarayanan ,
R. R. Mueller ,
R. Petkovic-Luton  and
J. W. Steeds
Raghavan Ayer
Affiliation:
Exxon Research & Engineering Company, Annandale, New Jersey 08801
J. C. Scanlon
Affiliation:
Exxon Research & Engineering Company, Annandale, New Jersey 08801
T. A. Ramanarayanan
Affiliation:
Exxon Research & Engineering Company, Annandale, New Jersey 08801
R. R. Mueller
Affiliation:
Exxon Research & Engineering Company, Annandale, New Jersey 08801
R. Petkovic-Luton
Affiliation:
Exxon Research & Engineering Company, Annandale, New Jersey 08801
J. W. Steeds
Affiliation:
University of Bristol. Bristol. United Kingdom
Get access

Abstract

The crystal structure and chemical composition of the intermetallic phase in a Fe-20%Cr-4%Al-0.5%Y (wt. %) alloy were investigated by electron microscopy. Convergent beam diffraction studies revealed that the intermetallic phase forms in three different crystal structures that could coexist in a single grain of the phase. The dominant crystal structure was shown to be hexagonal (a = 0.85, c = 0.84 nm) with a space group most likely to be P63/mmc. Within the hexagonal phase, regions of a rhombohedral crystal structure (a = 0.85, c = 1.26 nm) were observed that had grown in without an apparent phase boundary separating the two crystal structures. The third crystal structure was determined to be monoclinic (a = 0.97, b = 0.85, c = 1.07 nm, and beta = 97.3°) and formed by twinning on the {10$\overline 1$1} planes of the hexagonal phase. The chemical compositions of regions with different crystal structures were comparable and the stoichiometry of the intermetallic phase corresponds to (Fe,Cr)17 (Al,Y)2. The relationship of the observed crystal structures to those previously reported is discussed.

Type
Articles
Information
Journal of Materials Research , Volume 2 , Issue 1 , February 1987 , pp. 16 - 27
Copyright
Copyright © Materials Research Society 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Tien, J. K. and Petit, F. S., Metall. Trans. A 3, 1587 (1972).CrossRefGoogle Scholar
2Kuengly, J. D. and Douglass, D. L., Oxid. Met. 8, 139 (1974).Google Scholar
3Golightly, F. A., Stott, F. H., and Wood, G. C., Oxid. Met. 10, 163 (1976).Google Scholar
4Golightly, F. A., Stott, F. H., and Wood, G. C., J. Electrochem. Soc. 126, 1035 (1979).CrossRefGoogle Scholar
5Allam, I. M., Whittle, D. P., and Stringer, J., Oxid. Met. 12, 35 (1978).Google Scholar
6Pivin, J. C., Delaunay, D., Roques-Carmes, C., Huntz, A. M., and Lacombe, P., Corros. Sci. 20, 351 (1980).CrossRefGoogle Scholar
7Delaunay, D. and Huntz, A. M., J. Mater. Sci. 17, 2027 (1982).Google Scholar
8Whittle, D. P. and Stringer, J., Philos. Trans. R. Soc. London Ser. A 295, 309 (1980).Google Scholar
9Benjamin, J. S., Metal. Trans. 1, 2943 (1970).CrossRefGoogle Scholar
10Ramanarayanan, T. A., Raghavan, M., and Petkovic-Luton, R., J. Electrochem. Soc. 131, 923 (1984). UR. Ayer, T. A. Ramanarayanan, and R. Petkovic-Luton (unpublished work).CrossRefGoogle Scholar
12Steeds, J. W., Introduction to Analytical Microscopy, edited by Hren, J. J., Goldstein, J. I., and Joy, D. C. (Plenum, New York, 1979), p. 387.Google Scholar
13Raghavan, M., Scanlon, J. C., and Steeds, J. W., Metal. Trans. 15, 1299 (1984).CrossRefGoogle Scholar
14Buschow, K. H. J., J. Less Common Metals 11, 204 (1966).CrossRefGoogle Scholar
15Florio, J. V., Baenziger, N. C., and Rundle, R. E., Acta Crystallogr. 9, 367 (1956).Google Scholar
16Pearson, W. B., The Crystal Chemistry and Physics of Metals and Alloys (Wiley, New York, 1972), p. 364.Google Scholar
17Johnson, Q., Smith, G. S., and Wood, D. H., Acta. Crystallogr. 258, 464 (1969).CrossRefGoogle Scholar