Phase transformation in titanium induced by laser heating at high pressure

Journal Article · Fri Jul 15 00:00:00 EDT 1994 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(94)90169-4· OSTI ID:7037850

Gu, G; Vohra, Y K ^[1]; Brister, K E ^[2]

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1. Univ. of Alabama, Birmingham, AL (United States). Dept. of Physics
2. Cornell Univ., Ithaca, NY (United States). Cornell High Energy Synchrotron Source

Group IV transition metals in the Periodic Table (Ti, Zr and Hf) are expected to have a hcp[r arrow][omega][r arrow]bcc structural phase transformation sequence under ultra high pressure conditions. This structural transformation sequence is driven by the changes in electronic structure that are induced by s-band to d-band electron transfer under compression. At ambient conditions, these three elements all crystallize in the hcp([alpha]) phase. At high temperature and ambient pressure, they transform to bcc([beta]) phase. At room temperature and high pressure they transform to [omega] phase. The observed [alpha][r arrow][omega] transformation pressure shows strong dependence on impurity content, strain rate, and microstructural effects. Under static pressures, transformation pressure from [alpha] phase to [omega] phase is at 2 GPa for Ti and Zr, and 38 GPa for Hf. At room temperature, the phase transformation pressure from [omega] phase to [beta] phase was observed at 30 GPa in Zr and 76 GPa in Hf. So far, the [omega][r arrow][beta] phase transformation has not been observed in pure titanium at high pressure and room temperature. The recent theoretical calculation shows the transformation from [omega] phase to [beta] phase is expected to occur at 57.5 GPa at 0 Kelvin in titanium. The present studies are motivated by phase transformations in transition metals and alloys under combined static high pressure and laser heating treatment.

• OSTI ID: 7037850
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 31:2; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TITANIUM
CRYSTAL-PHASE TRANSFORMATIONS
EXPERIMENTAL DATA
LASER RADIATION
PHASE STUDIES
PRESSURE DEPENDENCE
DATA
ELECTROMAGNETIC RADIATION
ELEMENTS
INFORMATION
METALS
NUMERICAL DATA
PHASE TRANSFORMATIONS
RADIATIONS
TRANSITION ELEMENTS
360102* - Metals & Alloys- Structure & Phase Studies