Temperature dependence of the. omega. -bcc phase transition in zirconium metal
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York (USA)
High-pressure, high-temperature energy-dispersive x-ray diffraction studies were carried out on the group-IV transition-metal zirconium (Zr) to 36 GPa using a synchrotron-radiation source to investigate the entropy contribution in the {omega}- to-bcc phase transition. A room-temperature equilibrium transformation pressure of 35{plus minus}3 GPa between the {omega} and bcc phases of Zr metal was observed. A negative slope of 39{plus minus}5 K/GPa along the {omega}-bcc phase boundary observed in this experiment gives experimental evidence indicating thermal contribution to the structural sequences in transition metals and shows that the {omega} phase of Zr metal (a phase of group-IV transition metals) has lower entropy than its pressure-induced bcc phase (isostructural with group-V transition metals). Extrapolation of the present data indicates that the previous observation of a phase transition in shock-wave experiments at 26 GPa and 540 K is due to this {omega}-to-bcc phase transition.
- DOE Contract Number:
- FG02-87ER45320
- OSTI ID:
- 6004686
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 44:18; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
BREMSSTRAHLUNG
ELECTROMAGNETIC RADIATION
ELEMENTS
ENTROPY
HIGH TEMPERATURE
METALS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
RADIATIONS
SHOCK WAVES
SYNCHROTRON RADIATION
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS
TRIPLE POINT
VERY HIGH PRESSURE
ZIRCONIUM