Melting in alkali-metal--lead alloys: KPb and CsPb

Journal Article · Tue Oct 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.7289· OSTI ID:5208263

Price, D L; Saboungi, M ^[1]

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1. Argonne National Laboratory, Argonne, Illinois (USA)

Inelastic neutron-scattering measurements have been made on KPb and CsPb alloys at various temperatures in the solid and liquid states. In the thermodynamic data CsPb exhibits two transitions near the melting point at 869 and 920 K. In the intermediate phase, quasielastic broadening is observed, indicating that the phase is a plastic crystal characterized by rapid reorientations of structural units. The results are well reproduced by a simple model describing independent jump reorientations of Cs{sub 4}Pb{sub 4} units between the four orientations found in the crystal at room temperature. KPb on the other hand has a single melting transition at 862 K, and no quasielastic broadening is observed below this temperature, indicating that translational and orientational order disappear simultaneously. The model for jump reorientations in CsPb also explains previous neutron-diffraction results for the intermediate phase.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5208263
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:14; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
AMBIENT TEMPERATURE
CESIUM ALLOYS
COHERENT SCATTERING
DIFFRACTION
HIGH TEMPERATURE
INELASTIC SCATTERING
LEAD ALLOYS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MELTING
NEUTRON DIFFRACTION
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PLASTICITY
POTASSIUM ALLOYS
SCATTERING
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES