Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-08T00:24:58.201Z Has data issue: false hasContentIssue false

The effect of composition and cooling rate on the structure of rapidly solidified (Fe, Ni)3Al–C alloys

Published online by Cambridge University Press:  31 January 2011

S. A. Myers
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, North Carolina 27695-7907
C. C. Koch
Affiliation:
Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, North Carolina 27695-7907
Get access

Abstract

There is controversy in the literature regarding the existence of the metastable γ′ phase with an ordered Ll2 structure in rapidly solidified Fe–Ni–Al–C alloys. In this study, the quench rate–metastable structure dependence was examined in the Fe–20Ni–8Al–2C (weight percent) alloy. The effect of silicon on the kinetics of phase formation was studied by adding two weight percent silicon to a base alloy of Fe–20Ni–8Al–2C. Samples were rapidly solidified in an arc hammer apparatus and examined by transmission electron microscopy. In the Fe–20Ni–8Al–2C alloy, the nonequilibrium γ′ and γ phases were found in foils 65 to 100 μm thick. At higher quench rates, i.e., thinner samples, the matrix was observed to be disordered fcc γ with K-carbide precipitates. Samples containing silicon were found to have a matrix composed of γ′ and γ structures when the foils were thicker than 40 μm. At higher quench rates, the matrix was disordered fcc γ with K-carbide precipitates. The nonequilibrium γ′ and γ structures are present in samples with or without silicon, but are observed at higher cooling rates with the addition of silicon. This sensitivity to cooling rate and composition in resulting metastable structures may explain the differences reported in the literature for these rapidly solidified materials.

Type
Articles
Copyright
Copyright © Materials Research Society 1989

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

1Inoue, A., Minemura, T., Kitamura, A., and Masumoto, T., Metall. Trans. A 12A, 1041 (1981).CrossRefGoogle Scholar
2Han, K. H. and Choo, W. K., Metall. Trans. A 14A, 973 (1983).CrossRefGoogle Scholar
3Sun, Z., Davies, H. A., and Whiteman, J. A., Met. Sci. 18, 459 (1984).CrossRefGoogle Scholar
4Chen, H.T., Myers, S.A., and Koch, C.C., Mat. Sci. and Eng. 98, 277 (1988).CrossRefGoogle Scholar
5Inoue, A., Arnberg, L., Lehtinen, B., and Masumoto, T., Metall. Trans. A 17A, 2077 (1986).CrossRefGoogle Scholar
6International Tables for X-ray Crystallography (Birmingham, Knyoch Press 1962) III 216.Google Scholar
7Oshima, R. and Wayman, C.M., Metall. Trans. A 3, 2163 (1972).CrossRefGoogle Scholar
8Choo, W.K. and Kim, D.G., Metall. Trans. A 18A, 759 (1987).CrossRefGoogle Scholar
9Hayzeldon, C., Ph.D. Thesis, Univ. of Sussex, 1983.Google Scholar