Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-19T05:50:42.214Z Has data issue: false hasContentIssue false

Nu-Phase in Fe-Al-B Alloys

Published online by Cambridge University Press:  02 July 2020

M. F. Chisholm
Affiliation:
Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN37831
G. Duscher
Affiliation:
Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN37831
Lixin Pang
Affiliation:
Division of Engineering, Brown University, Providence, RI02912
K. S. Kumar
Affiliation:
Division of Engineering, Brown University, Providence, RI02912
Get access

Extract

FeAl alloys with 40 to 50 at % Al have an impressive combination of oxidation and sulfidation resistance, low density, and low cost and are thus considered as possible substitutes for stainless steels. However, before these materials can be used in structural applications, the fracture characteristics of the alloy's grain boundaries need to be improved. Small additions of carbon and boron have been considered and the resulting properties have been reported. Boron is found to prevent intergranular fracture in iron-rich alloys and to mitigate environmental embrittlement although the improvement is not as dramatic as is seen with Ni3Al alloyed with boron. Boron segregates to the grain boundaries in Fe-Al alloys and boride precipitates at the boundaries and within the grains have been observed.

In this paper, we report the composition and atomic arrangement in a recently discovered phase (designated v phase) found in Fe-Al alloys containing small boron additions using a combination of Z-contrast imaging and electron energy-loss spectroscopy.

Type
The Theory and Practice of Scanning Transmission Electron Microscopy
Copyright
Copyright © Microscopy Society of America

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

1.Pang, L. and Kumar, K. S., in Structural Intermetalics 1997, (TMS, Warrendale, PA, 1997) p.703.Google Scholar
2.Crimp, M. A. and Vendula, K., Mater. Sci. and Eng., 78, 193 (1986).CrossRefGoogle Scholar
3.Liu, C. T. and George, E. P., Scripta Metall., 24 1285 (1990).CrossRefGoogle Scholar
4.Gaydosh, D. J., Draper, S. L. and Nathal, M. V., Metall. Trans., 20A, 1701 (1989).CrossRefGoogle Scholar
5.Pang, L. and Kumar, K. S., Phil. Mag. Lett., 76, 323 (1997).CrossRefGoogle Scholar
6.Pierron, X. and Baker, I., in High Temperature Structural Intermetallic Alloys VII, (MRS, Warrendale, PA, 1997) p.331.Google Scholar
7. Note that, although the periodicity along the projection direction is not obvious from this single view, the images of the orthogonal <100> projection and their corresponding electron diffraction patterns indicate the periodicity in the <100> direction is the same as that of the B2 matrix.+projection+and+their+corresponding+electron+diffraction+patterns+indicate+the+periodicity+in+the+<100>+direction+is+the+same+as+that+of+the+B2+matrix.>Google Scholar
8.Vitek, V., Smith, D. A. and Pond, R. C., Phil. Mag., 41A, 649 (1980).CrossRefGoogle Scholar
9.Hashimoto, M., Ishida, Y., Yamamoto, R. and Doyama, M., Acta Metall., 32, 1 (1984).CrossRefGoogle Scholar
10.Egerton, R. F., Electron Energy-Loss Spectroscopy in the Electron Microscope, (Plenum Press, New York, 1996).CrossRefGoogle Scholar
11.Pearson, D. H., Fultz, B. and Ahn, C. C., Appl. Phys. Lett, 53, 1407, (1988).CrossRefGoogle Scholar
12. This research was supported by U. S. Department of Energy under contract DE-AC05-96OR22464 and the Office of Naval Research under contract N00014-95-1-0564.Google Scholar