The Elastic Moduli of Monoclinic and Orthorhombic Plutonium

ORAL

Abstract

Measurements were made of the bulk and shear moduli of high-purity polycrystalline Pu from 10K to 670K using resonant ultrasound spectroscopy. A simple dilatometer was employed to provide redundant detection of the phase transitions. We observed the expected phase transitions from monoclinic ($\alpha )$ to body centered monoclinic ($\beta )$ to orthorhombic ($\gamma )$ to face centered cubic ($\delta )$. Very accurate values were obtained for $\alpha $-Pu, $\beta $-Pu was very soft and difficult to analyze, as was $\delta $-Pu. Surprisingly, the $\gamma $-phase produced the high-Q resonances needed for accurate elastic modulus determination. We discuss also the unusual temperature dependences.

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Authors

  • Albert Migliori

    • National High Magnetic Field Laboratory, Pulsed Field Facility, LANL, Los Alamos, NM 87545
    • National High Magnetic Filed Laboratory-LANL, Los Alamos, NM
    • Los Alamos National Laboratory
    • 1
    • NHMFL / LANL

  • Jon Betts

    • National High Magnetic Field Laboratory, Pulsed Field Facility, LANL, Los Alamos, NM 87545
    • Los Alamos National Laboratory
    • NHMFL / LANL

  • Cristian Pantea

    • Los Alamos National Laboratory
    • 1

  • I. Mihut

    • National High Magnetic Filed Laboratory-LANL, Los Alamos, NM
    • Los Alamos National Laboratory

  • C. Mielke

    • Los Alamos National Laboratory, National High Magnetic Field Laboratory
    • Los Alamos National Laboratory

  • J.N. Mitchell

    • Los Alamos National Laboratory