Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-30T20:55:40.715Z Has data issue: false hasContentIssue false
  • English
  • Français

A microstructural study of rapidly solidified and heat-treated austenitic Fe–Mn−Al–Mo–W–Nb–C alloys

Published online by Cambridge University Press:  03 March 2011

Kwan H. Han  and
Hyun E. Lee
Kwan H. Han*
Affiliation:
Department of Metallurgical Engineering, Yeungnam University, 214–1 Dae-Dong, Kyongsan, Kyongbuk 712–749, Korea
Hyun E. Lee
Affiliation:
Department of Metallurgical Engineering, Yeungnam University, 214–1 Dae-Dong, Kyongsan, Kyongbuk 712–749, Korea
*
a)Address correspondence to this author.
Get access

Abstract

The microstructural characteristics of melt-spun and heat-treated austenitic Fe−28Mn−8.6Al−0.5Mo−0.7W−0.5Nb−1.1C (in wt. %) alloys have been investigated by means of transmission electron microscopy. The melt-spun alloy contained fine austenitic cells and some intercelluar Nb(C, N) precipitates. Detailed observations revealed fine {100} modulations in the matrix of the cells, as well as a concomitant L′I2 atomic ordering arising from it. These observations indicate that the onset of decomposition of the initial austenite phase occurred during the rapid solidification process. Aging of the melt-spun alloy at 823–1173 K produced various microstructures, including a general precipitation of Nb(C, N) in the matrix. On isochronal annealing for 1 h, this matrix Nb(C, N) precipitation commenced at 1073 K with the formation of metastable coherent K-carbide (K′) near cell boundaries. On annealing at temperatures above 1123 K, only the Nb(C, N) precipitates were formed, on a fine scale, being accompanied by the formation of precipitate-free regions in the vicinity of cell and grain boundaries. Both intercellular and matrix Nb(C, N) precipitates obeyed a cube-to-cube orientation relationship with austenite. The general matrix precipitation of Nb(C, N) and formation of precipitate-free regions are discussed in terms of a vacancy (defect)-depletion effect. Finally, it was demonstrated that, by employing a double heat-treatment schedule of annealing at 1173 K followed by aging at 823 K, a novel microstructure consisting of fine dispersoids of Nb(C, N) carbo-nitride, distributed over the matrix of {100} modulated structure, could be produced.

Type
Articles
Information
Journal of Materials Research , Volume 10 , Issue 6 , June 1995 , pp. 1371 - 1378
Copyright
Copyright © Materials Research Society 1995

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

1James, P. J., J. Iron Steel Inst. 207, 54 (1969).Google Scholar
2Kayak, G. L., Met. Sci. Heat Treat. 11, 95 (1969).CrossRefGoogle Scholar
3Krivonogov, G. S., Alekseyenko, M. F., and Solov'yeva, G.G., Phys. Met. Metall. 39, 86 (1975).Google Scholar
4Han, K. H., Choo, W. K., Choi, D. Y., and Hong, S. P., Alternate Alloying for Environmental Resistance, edited by Banerji, S. K. and Smolik, G.R. (TMS-AIME, Warrendale, PA, 1987), p. 91.Google Scholar
5Storchak, N. A. and Drachinskaya, A. G., Phys. Met. Metall. 44, 123 (1977).Google Scholar
6Han, K. H., Yoon, J. C., and Choo, W. K., Scripta Metall. 20, 33(1986).Google Scholar
7Han, K. H. and Choo, W. K., Metall. Trans. 20A, 205 (1989).CrossRefGoogle Scholar
8Han, K. H., Choo, W. K., and Laughlin, D. E., Scripta Metall. 22, 1873 (1988).CrossRefGoogle Scholar
9Alekseenko, M. F., Krivonogov, G. S., Kozyreva, L. G., Kachanova, I. M., and Arapova, L. V., Met. Sci. Heat Treat. 14, 187(1972).CrossRefGoogle Scholar
10Kalashinikov, I. S., Litvinov, V. S., Khadyyev, M. S., and Chumakova, L. D., Phys. Met. Metall. 57, 160 (1984).Google Scholar
11Karakishev, S. D., Chumakova, L. D., Kalashinikov, I. S., and Senchenko, A. A., Met. Sci. Heat Treat. 28 (7–8), 609 (1987).Google Scholar
12Wood, J. V. and Honeycombe, R. W. K., Mater. Sci. Eng. 23, 107 (1976).CrossRefGoogle Scholar
13Wood, J. V. and Honeycombe, R. W. K., Philos. Mag. A37, 501 (1978).CrossRefGoogle Scholar
14Han, K. H. and Lee, H. E., Scripta Metall. et Mater. 30, 441 (1994).CrossRefGoogle Scholar
15Wood, J. V. and Honeycombe, R. W. K., J. Mater. Sci. 9, 1183 (1974).CrossRefGoogle Scholar
16Cahn, J. W., Acta Metall. 10, 179 (1962).CrossRefGoogle Scholar
17Daniel, V. and Lipson, H., Proc. R. Soc. London A181, 368 (1943).Google Scholar
18Han, K. H. and Choo, W. K., Metall. Trans. 14A, 973 (1983).CrossRefGoogle Scholar
19Karakishev, S. D. and Kalashinikov, I. S., Phys. Met. Metall. 62, 187 (1986).Google Scholar
20Silcock, J. M., J. Iron Steel Inst. 201, 125 (1963).Google Scholar
21Dewey, M. A. P., Sumner, G., and Brammer, I. S., J. Iron Steel Inst. 203, 938 (1965).Google Scholar
22Davenport, A. T., Brossard, L. C., and Miner, R. E., J. Met. 27, 21 (1975).Google Scholar
23Kachaturyan, A. G., Theory of Structural Transformations in Solids (John Wiley & Sons, Inc., New York, 1983), p. 315.Google Scholar
24van Aswegen, J. S. T. and Honeycombe, R. W. K., Acta Metall. 10, 262 (1962).CrossRefGoogle Scholar
25van Aswegen, J. S. T., Honeycombe, R. W. K., and Warrington, D. H., Acta Metall. 12, 1 (1964).CrossRefGoogle Scholar
26Silcock, J. M. and Tunstall, W. J., Philos. Mag. 10, 361 (1964).CrossRefGoogle Scholar
27Shepherd, J. P., Metall. Sci. J. 3, 229 (1969).Google Scholar
28Thomas, G. and Willens, R. H., Acta Metall. 12, 191 (1968).CrossRefGoogle Scholar
29Nordberg, H. and Aaronson, B., J. Iron Steel Inst. 206, 263 (1968).Google Scholar