Thermodynamics of the bulk modulus of delta phase plutonium alloys

ABSTRACT

The purpose of this paper is to show that most of the large observed value of dB/dT arises from anharmonic lattice vibrations. This contrasts with the situation for the observed anomalous thermal expansion, which arises from an Invar, or two-level, phenomenon. Anharmonic effects appear also in the heat capacity at temperatures close to the δ $\to$ ε transformation temperature. The analysis rests on the Grüneisen assumption, that the pressure is proportional to the internal energy.

KEYWORDS:

• Actinides
• elasticity
• thermal properties
• plutonium

Acknowledgements

The author thanks his long-time collaborators Joyce Roberts and Barbara Katz.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the U.S. Department of Energy.