Skip to main content Accessibility help
×
Home

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

  • J. Zhou (a1) and L.M. Hsiung (a1)

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.

Copyright

Corresponding author

a) Address all correspondence to this author. e-mail: hsiung1@llnl.gov

References

Hide All
1.Bates, L.F., Barnard, R.D.: Electrical and magnetic properties of uranium-niobium system. Proc. Phys. Soc. London 78, 361 (1961).
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).
3.Magness, L.S.: High-strain rate deformation behavior of kinetic-energy penetrator materials during ballistic impact. Mech. Mater. 17, 147 (1994).
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).
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).
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).
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).
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).
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).
10.Jackson, R.J., Miley, D.V.: Tensile properties of gamma quenched and aged uramium-based niobium alloys. ASM Trans. 61, 336 (1968).
11.Orlov, K., Teplinskaya, V.M., Chebotarev, N.T.: Decomposition of a metastable solid solution in uranium-molybdenum alloy. Atomic Energy 88, 42 (2000).
12.Vandermeer, R.A.: Phase transformations in a uranium + 14 at.% niobium alloy. Acta Metall. 28, 383 (1980).
13.Beverini, G., Edmonds, D.V.: An APFIM study of the aging behavior of U–6 wt-percent Nb. J. Phys. 50, C8429 (1989).
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).
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).
16.Edington, J.W.: Practical Electron Microscopy in Materials Science (Van Nostrand Reinhold, New York, 1976).
17.Easterling, K.E., Porter, D.A.: Phase Transformation in Metals and Alloys (CRC Press, London, UK, 1992).
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.
19.Cahn, J.W.: “Spinodal Decomposition,” The 1967 Institute of Metals Lecture. Trans. TMS and AIME 242, 166 (1968).
20.Mbaye, A.A., Ferreira, L.G., Zunger, A.: 1st-principles calculation of semiconductor-alloy phase diagrams. Phys. Rev. Lett. 58, 49 (1987).
21.Zhao, J.C., Notis, M.R.: Ordering transformation and spinodal decomposition in Au–Ni alloys. Metall. Mater. Trans. 30A, 707 (1999).
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).
23.Butler, E.P., Thomas, G.: Structure and properties of spinodally decomposed Cu–Ni–Fe alloys. Acta Metall. 18, 347 (1970).

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed