Grüneisen analysis of thermodynamic properties of δ-phase Pu–Ga alloys

Abstract

We present a Grüneisen analysis of the intriguing temperature dependence of the thermal expansion and bulk modulus of delta phase plutonium alloys. This analysis exploits the thermodynamic relationship between these quantities and the heat capacity and reduces the description of complicated behaviour to the determination of a manageable number of numerical constants. We conclude from the analysis (1) that there is a small Schottky-like heat capacity anomaly at high temperatures and (2) that the size of this anomaly depends strongly on alloy concentration. Grüneisen analysis provides an economical description of the thermal expansion and bulk modulus of δ-Pu.

Keywords:

• actinides
• thermal expansion
• elasticity

Acknowledgements

We are pleased to thank Tongsik Lee and Gerry Lander for many useful discussions. Research was performed under the auspices of the United States Department of Energy. This work has benefited from the use of NPD at the Lujan Center at Los Alamos Neutron Science Center, funded by DOE Office of Basic Energy Sciences. Los Alamos National Laboratory is operated by Los Alamos National Security LLC under DOE Contract DE-AC52-06NA25396.