Crystal structures of group IVa metals at ultrahigh pressures
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY (USA)
High-pressure energy-dispersive x-ray-diffraction studies were carried out on the group IVa metals hafnium (Hf) to 252 GPa (to a volume compression {ital V}/{ital V}{sub 0} of 0.48) and titanium (Ti) to 87 GPa using a synchrotron source. Two new structural phase transformations between an hcp phase and an {omega} phase and between the {omega} phase and a bcc phase (isostructural with group V transition metals) were observed during both compression and decompression in Hf. Equilibrium transformation pressures for Hf are 38{plus minus}8 and 71{plus minus}1 GPa for the hcp-to-{omega} and {omega}-to-bcc phase transformations, respectively, at room temperature. In Ti, only the hcp-to-{omega} phase transition was observed above 8 GPa, and the {omega} phase was stable to 87 GPa. The crystal structure sequences of Ti, Zr, and Hf at ultrahigh pressures are discussed.
- OSTI ID:
- 6174997
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:10; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
BCC LATTICES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
CUBIC LATTICES
ELEMENTS
EQUATIONS
EQUATIONS OF STATE
HAFNIUM
HCP LATTICES
HEXAGONAL LATTICES
METALS
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
TITANIUM
TRANSITION ELEMENTS
VERY HIGH PRESSURE
ZIRCONIUM