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Long-term phase instability in a water-quenched uranium alloy

Published online by Cambridge University Press:  01 April 2006

J. Zhou  and
L.M. Hsiung
J. Zhou
Affiliation:
Lawrence Livermore National Laboratory, Chemistry and Materials Science Directorate, Livermore, California 94551-9900
L.M. Hsiung*
Affiliation:
Lawrence Livermore National Laboratory, Chemistry and Materials Science Directorate, Livermore, California 94551-9900
*
a) Address all correspondence to this author. e-mail: hsiung1@llnl.gov
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Abstract

The U–6 wt% Nb (U6Nb) alloy in the water-quenched (WQ) state has been in service for a number of years. Its long-term reliability is affected by the changes of the alloy microstructure and mechanical properties during service. In this paper, the water quenched U–6 wt% Nb (WQ-U6Nb) alloy in service for 15 years at ambient temperatures was studied using an analytical transmission electron microscopy (TEM) analysis. We found that the long-term natural aging resulted in a disorder–order phase transformation, leading to the formation of anti-phase boundaries (APBs). The newly found ordered phase was then identified by proposing two phase transform schemes, which were also discussed with regards to the potential subsequence of the microstructural evolution for the alloy in further service. The initial study also provides convincing evidence for the disorder–order transformation, which has been predicted by numerous studies to be a transient thermodynamic event before spinodal decomposition. This suggests that the long-term naturally aged WQ–U6Nb is a good model alloy to study thermodynamic and kinetic phenomena requiring chronic processes.

Keywords

Crystallographic structurePhase transformationTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 21 , Issue 4 , April 2006 , pp. 904 - 909
Copyright
Copyright © Materials Research Society 2006

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References

REFERENCES

1.Bates, L.F., Barnard, R.D.: Electrical and magnetic properties of uranium-niobium system. Proc. Phys. Soc. London 78, 361 (1961).CrossRefGoogle Scholar
2.Suski, W., Czopnik, A., Solyga, M., Wochowski, K., Mydlarz, T.: Magnetic, electrical and thermodynamic properties of the UCu6Al6 derivatives. Phys. B, Condens. Matter 359, 1024 (2005).CrossRefGoogle Scholar
3.Magness, L.S.: High-strain rate deformation behavior of kinetic-energy penetrator materials during ballistic impact. Mech. Mater. 17, 147 (1994).CrossRefGoogle Scholar
4.Nakamura, K., Ogata, T., Kurata, M., Yokoo, T., Mignanelli, M.A.: Reactions of uranium-plutonium alloys with iron. J. Nucl. Sci. Technol. 38, 112 (2001).CrossRefGoogle Scholar
5.Kelly, D., Lillard, J.A., Manner, W.L., Hanrahan, R., Paffett, M.T.: Surface characterization of oxidative corrosion of U-Nb alloys. J. Vac. Sci. Technol. A, Vac. Surf. Films 19, 1959 (2001).CrossRefGoogle Scholar
6.Eckelmeyer, K.H., Romig, A.D., and Weirick, L.J.: The effects of quench rate on the microstructure, mechanical properties, and corrosion behavior of U-6 WT PCT Nb, Metall. Trans. A, Phys. Metall. Mater. Sci. 15, 1319 (1984).CrossRefGoogle Scholar
7.Addessio, F.L., Zuo, Q.H., Mason, T.A., Brinson, L.C.: Model for high-strain-rate deformation of uranium-niobium alloys. J. Appl. Phys. 93, 9644 (2003).CrossRefGoogle Scholar
8.Vandermeer, R.A., Ogle, J.C., and Northcutt, W.G.: A phenomenological study of the shape memory effect in polycrystal uranium niobium alloys, Metall. Trans. A, Phys. Metall. Mater. Sci. 12, 733 (1981).CrossRefGoogle Scholar
9.Field, R.D., Brown, D.W., Thomas, D.J.: Texture development and deformation mechanisms during uniaxial straining of U–Nb shape-memory alloys. Philos. Mag. 85, 1441 (2005).CrossRefGoogle Scholar
10.Jackson, R.J., Miley, D.V.: Tensile properties of gamma quenched and aged uramium-based niobium alloys. ASM Trans. 61, 336 (1968).Google Scholar
11.Orlov, K., Teplinskaya, V.M., Chebotarev, N.T.: Decomposition of a metastable solid solution in uranium-molybdenum alloy. Atomic Energy 88, 42 (2000).CrossRefGoogle Scholar
12.Vandermeer, R.A.: Phase transformations in a uranium + 14 at.% niobium alloy. Acta Metall. 28, 383 (1980).CrossRefGoogle Scholar
13.Beverini, G., Edmonds, D.V.: An APFIM study of the aging behavior of U–6 wt-percent Nb. J. Phys. 50, C8429 (1989).Google Scholar
14.Koike, J., Kassner, M.E., Tate, R.E., and Rosen, R.S.: The Nb–U (niobium-uranium) system. J. Phase Equilib. 19, 253 (1998).CrossRefGoogle Scholar
15.Sunwoo, A.J., Hiromoto, D.S.: Effects of natural aging on the tensile properties of water-quenched U–6%Nb alloy. J. Nucl. Mater. 327, 37 (2004).CrossRefGoogle Scholar
16.Edington, J.W.: Practical Electron Microscopy in Materials Science (Van Nostrand Reinhold, New York, 1976).Google Scholar
17.Easterling, K.E., Porter, D.A.: Phase Transformation in Metals and Alloys (CRC Press, London, UK, 1992).Google Scholar
18.Hsiung, L.M., Briant, C.L., Chasse, K.R.: Low-temperature aging and phase stability of U6Nb, in Actinides—Basic Science, Applications and Technology, edited by Soderholm, L., Joyce, J.J., Nicol, M.F., Shuh, D.K., and Tobin, J.G. (Mater. Res. Soc. Proc. 802, Warrendale, PA, 2004), DD1.6, p. 21.Google Scholar
19.Cahn, J.W.: “Spinodal Decomposition,” The 1967 Institute of Metals Lecture. Trans. TMS and AIME 242, 166 (1968).Google Scholar
20.Mbaye, A.A., Ferreira, L.G., Zunger, A.: 1st-principles calculation of semiconductor-alloy phase diagrams. Phys. Rev. Lett. 58, 49 (1987).CrossRefGoogle Scholar
21.Zhao, J.C., Notis, M.R.: Ordering transformation and spinodal decomposition in Au–Ni alloys. Metall. Mater. Trans. 30A, 707 (1999).Google Scholar
22.Sato, K., Stobbs, W.M.: Quantification of the spinodal wave in Cu2.5Mn0.5Al by dark-field image analysis. Philos. Mag. A, Phys. Condens. Matter Struct. Def. Mech. Prop. 69, 349 (1994).Google Scholar
23.Butler, E.P., Thomas, G.: Structure and properties of spinodally decomposed Cu–Ni–Fe alloys. Acta Metall. 18, 347 (1970).CrossRefGoogle Scholar