Crystal structures of group IVa metals at ultrahigh pressures

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.6736· OSTI ID:6174997

Xia, H; Parthasarathy, G; Luo, H; Vohra, Y K; Ruoff, A L ^[1]

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1. 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), Vol. 42:10; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
HAFNIUM
CRYSTAL STRUCTURE
TITANIUM
ZIRCONIUM
BCC LATTICES
CRYSTAL-PHASE TRANSFORMATIONS
EQUATIONS OF STATE
HCP LATTICES
PRESSURE DEPENDENCE
VERY HIGH PRESSURE
CRYSTAL LATTICES
CUBIC LATTICES
ELEMENTS
EQUATIONS
HEXAGONAL LATTICES
METALS
PHASE TRANSFORMATIONS
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies