Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-25T03:27:12.706Z Has data issue: false hasContentIssue false
  • English
  • Français

Oxidation of Single-Crystal γ′-Ni3A1 at Low Oxygen Partial Pressure

Published online by Cambridge University Press:  26 February 2011

E. Schumann ,
G. Schnotz ,
U. Salzberger  and
M. Rühle
E. Schumann
Affiliation:
MPI für Metallforschung, Institut für Werkstoffwissenschaft, Seestrasse 92, D-7000 Stuttgart 1, Germany
G. Schnotz
Affiliation:
MPI für Metallforschung, Institut für Werkstoffwissenschaft, Seestrasse 92, D-7000 Stuttgart 1, Germany
U. Salzberger
Affiliation:
MPI für Metallforschung, Institut für Werkstoffwissenschaft, Seestrasse 92, D-7000 Stuttgart 1, Germany
M. Rühle
Affiliation:
MPI für Metallforschung, Institut für Werkstoffwissenschaft, Seestrasse 92, D-7000 Stuttgart 1, Germany
Get access

Abstract

Single crystals of γ′-Ni3Al((001)-oriented) were oxidized at 1223 K under an oxygen partial pressure of ∼4 ×10−19 atm for times ranging from 0.1 to 50 hours. Microstructural development of the oxide scale and subscale metal was studied by electron microscopy. A special technique permitted the reproducible and efficient preparation of TEM cross section specimens. Initially, a fine-grained γ-Al2O3 scale formed with a preferred orientation. Depletion of Al from the γ′-Ni3Al resultedin a Ni-Al solid solution zone between the oxide scale and the intermetallic. After 20 hours oxidation, a discontinuous α-A12O3 layer between the γ-A12O3 and the metal was observed. The α-A12O3 layer exhibited a much larger grain size than that of the γ-A12O3 and was continuous after 50 hours oxidation. Formation of the α-A12O3 layer correlated with a decreasing parabolic oxidation rate constant kp, as measured by thermogravimetric analysis (TGA).

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 213: Symposium Q – High-Temperature Ordered Intermetallic Alloys IV , 1990 , 951
Copyright
Copyright © Materials Research Society 1991

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

[1] Hindam, H. M. and Smeltzer, W. W., J. Electrochem. Soc. 127, 1630 (1980).Google Scholar
[2] Smialek, J. L. and Gibala, R., Met. Trans. 14A, 2143 (1983).CrossRefGoogle Scholar
[3] Venezia, A. M. and Loxton, C. M., Surface Sci. 194, 136 (1988).Google Scholar
[4] Doychak, J., Smialek, J. and Mitchell, T.E., Met. Trans. A 20A, 499 (1989).Google Scholar
[5] Rybicki, G. C. and Smialek, J.L., Oxid. Met. 31 275 (1989).Google Scholar
[6] Doychak, J. and Rühle, M., Oxid. Met. 31, 431 (1989).CrossRefGoogle Scholar
[7] Singleton, M. F., Murray, J. L. and Nash, P., Binary Alloy Phase Diagrams (edited by Massalski, T. B.) vol. 1, p. 140 ASM, Metals Park, OH (1986).Google Scholar
[8] Elrefaie, F. A. and Smeltzer, W.W., J. Electrochem. Soc 128, 2237 (1981).Google Scholar
[9] Donlon, W. T., Mitchell, T. E., and Heuer, A. H., J. Mat. Sci. 17, 1389 (1982).Google Scholar
[10] Brumm, M. and Grabke, H. J., unpublished research (1990).Google Scholar