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A new high-strength spinodal alloy

Published online by Cambridge University Press:  01 April 2005

James A. Hanna*
Affiliation:
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
Ian Baker
Affiliation:
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
Markus W. Wittmann
Affiliation:
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755
Paul R. Munroe
Affiliation:
Electron Microscope Unit, University of New South Wales, Sydney, NSW 2052, Australia
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Preliminary investigations of a new high-strength alloy of composition Fe30Ni20Mn25Al25 (at.%) are described in this paper. The as-cast alloy consisted of a periodic two-phase microstructure of interconnected, ∼50-nm-wide rods with fully coherent {100} interfaces, strongly suggestive of formation by a B2 to [(B2 + body-centered cubic (bcc)] spinodal decomposition. The (Ni,Al)-rich B2 and (Fe,Mn)-rich bcc phases differed in lattice parameter by <0.5%. Hardness and yield strength of the as-cast alloy were found to be approximately 500 VPN and 1500 MPa, respectively, and increased by more than 50% after annealing at 550 °C for several days. (Fe,Mn)-rich precipitates with a β–Mn structure were observed in the annealed material.

Type
Rapid Communication
Copyright
Copyright © Materials Research Society 2005

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References

REFERENCES

1. Xiao, H. and Baker, I.: Long range order and defect concentrations in NiAl and CoAl. Acta Metall. Mater. 42, 1535 (1994).10.1016/0956-7151(94)90363-8CrossRefGoogle Scholar
2. Wittmann, M., Baker, I. and Munroe, P.: The structure and mechanical properties of Fe2AlMn single crystals. Philos. Mag. A 84, 3169 (2004).CrossRefGoogle Scholar
3. Jantzen, C. and Herman, H.: Spinodal decomposition––phase diagram representation and occurrence, in Phase Diagrams: Materials Science & Technology Vol. 5, edited by Alper, A. (Academic Press, New York, 1978), pp. 127185.Google Scholar
4. Hanna, J.: Investigations of Fe30Ni20Mn25Al25: A new high-strength spinodal alloy. M.S. Thesis, Thayer School of Engineering, Dartmouth College, Hanover, NH (2004).Google Scholar
5. Cahn, J.: Spinodal decomposition (1967 Institute of Metals Lecture). Trans. Metall. Soc. AIME 242, 166 (1968).Google Scholar
6. Cahn, J.: On spinodal decomposition in cubic crystals. Acta Metall. 10, 179 (1962).CrossRefGoogle Scholar
7. de Fontaine, D.: Configurational thermodynamics of solid solutions, in Solid State Physics Vol. 34: Advances in Research and Applications, edited by Seitz, F. (Academic Press, New York, 1979), pp. 73273.Google Scholar
8. Soffa, W. and Laughlin, D.: Decomposition and ordering processes involving thermodynamically first-order order → disorder transformations. Acta Metall. 37, 3019 (1989).CrossRefGoogle Scholar
9. Misra, A., Gibala, R. and Noebe, R.: Optimization of toughness and strength in multiphase intermetallics. Intermetallics 9, 971 (2001).CrossRefGoogle Scholar
10. Singh, J. and Wayman, C.: Age-hardening characteristics of a martensitic Fe–Ni–Mn alloy. Mater. Sci. Eng. 94, 233 (1987).CrossRefGoogle Scholar
11. Schwartz, L. and Plewes, J.: Spinodal decomposition in Cu–9 wt% Ni–6 wt% Sn—II. A critical examination of mechanical strength of spinodal alloys. Acta Metall. 22, 911 (1974).CrossRefGoogle Scholar
12. Kato, M., Mori, T. and Schwartz, L.: Hardening by spinodal modulated structure. Acta Metall. 28, 285 (1980).CrossRefGoogle Scholar
13. Munroe, P. and Baker, I.: Brittle fracture in B2 compounds, in George R. Irwin Symposium on Cleavage Fracture, edited by Chan, K. (TMS, Warrendale, PA, 1997), pp. 329345.Google Scholar
14. Gudladt, H-J., Wunderlich, W. and Costalas, E.: The influence of microstructure on the mechanical properties of a spinodally decomposed Cu–Ni–Fe alloy. Z. Metallkd. 88, 642 (1997).Google Scholar
15. Baker, I., Nagpal, P., Liu, F. and Munroe, P.: The effect of grain size on the yield strength of FeAl and NiAl. Acta Metall. Mater. 39(7), 1637 (1991).CrossRefGoogle Scholar