Hostname: page-component-5c6d5d7d68-ckgrl Total loading time: 0 Render date: 2024-08-21T23:08:08.255Z Has data issue: false hasContentIssue false
  • English
  • Français

“Burst-like” Characteristics of the δ/α′ Phase Transformation in Pu-Ga Alloys

Published online by Cambridge University Press:  01 February 2011

Kerri J.M. Blobaum ,
Christopher R. Krenn ,
Jeffery J. Haslam ,
Mark A. Wall  and
Adam J. Schwartz
Kerri J.M. Blobaum
Affiliation:
Chemistry and Materials Science Directorate, University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551
Christopher R. Krenn
Affiliation:
Chemistry and Materials Science Directorate, University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551
Jeffery J. Haslam
Affiliation:
Chemistry and Materials Science Directorate, University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551
Mark A. Wall
Affiliation:
Chemistry and Materials Science Directorate, University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551
Adam J. Schwartz
Affiliation:
Chemistry and Materials Science Directorate, University of California, Lawrence Livermore National Laboratory, Livermore, CA 94551
Get access

Abstract

The δ to α′ phase transformation in Pu-Ga alloys is intriguing for both scientific and technological reasons. On cooling, the ductile fcc δ-phase transforms martensitically to the brittle monoclinic α′-phase at approximately −120°C (depending on composition). This exothermic transformation involves a 20% volume contraction and a significant increase in resistivity. The reversion of α′ to δ involves a large temperature hysteresis and begins just above room temperature. In an attempt to better understand the underlying thermodynamics and kinetics responsible for these unusual features, we are examining the δ/α' transformations in a Pu-0.6 wt% Ga alloy using differential scanning calorimetry (DSC) and resistometry. Both techniques indicate that the martensite start temperature is −120°C and the austenite start temperature is 35°C. The heat of transformation is approximately 3 kJ/mole. During the α ′ → δ reversion, “spikes” and “steps” are observed in DSC and resistometry scans, respectively. These spikes and steps are periodic, and their periodicity with respect to temperature does not vary with heating rate. With an appropriate annealing cycle, including a “rest” at room temperature, these spikes and steps can be reproduced through many thermal cycles of a single sample.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 802: Symposium DD – Actinides - Basic Science, Applications, and Technology , 2003 , DD1.8
Copyright
Copyright © Materials Research Society 2004

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

1. Hecker, S. S. and Timofeeva, L. F., Los Alamos Science 26, 244 (2000).Google Scholar
2. Chebotarev, N. T., Smotriskaya, E. S., Andrianov, M. A., and Kostyuk, O. E., in Plutonium 1975 and other actinides, edited by Blank, H. and Lindner, R. (North Holland Publishing Co., Amsterdam, 1975), p. 37.Google Scholar
3. Orme, J. T., Faiers, M. E., and Ward, B. J., in Plutonium 1975 and other actinides, edited by Blank, H. and Lindner, R. (North-Holland Publishing Company, Amsterdam, 1975), p. 761.Google Scholar
4. Mitchell, J. N., Stan, M., Schwartz, D. S., and Boehlert, C. J., Metall. Mater. Trans., accepted for publication (2003).Google Scholar
5. Pijpers, T. F. J., Mathot, V. B. F., Goderis, B., Scherrenberg, R. L., and van der Vegte, E. W., Macromolecules 35, 3601 (2002).Google Scholar
6. Gibney, R. B. and Sandenaw, T. A., Los Alamos National Laboratory Report No. LA-1883 (1954).Google Scholar
7. Joel, J., Roux, C., and Rapin, M., J. Nucl. Mater. 40, 297 (1971).Google Scholar
8. Hecker, S. S., Harbur, D. R., and Zocco, T. G., Prog. in Mater. Sci., in press (2003).Google Scholar
9. Krenn, C. R., Modelling Simul. Mater. Sci. Eng., accepted for publication (2003).Google Scholar
10. Kitching, S., Planterose, P. G., and Gill, D. C., Plutonium Futures—The Science, Albuquerque, NM, 2003 (American Institute of Physics), p. 79.Google Scholar
11. Fluss, M. J., Wirth, B. D., Wall, M., Felter, T. E., Caturla, M. J., Kubota, A., and Rubia, T. Diaz de la, Alloys, J. and Compounds, in press (2003).Google Scholar