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Title: Structural phase stability in nanocrystalline titanium to 161 GPa

Nanocrystalline titanium (nc-Ti) metal was investigated up to 161 GPa at room temperature using a diamond anvil cell. X-ray diffraction and electrical resistance techniques were used to investigate the compressibility and structural phase stability. nc-Ti is observed to undergo three structural phase transitions at high pressures, starting with α → ω at 10GPa and followed by ω → γ at 127GPa and γ → δ at 140GPa. The observed structural phase transitions, as well as compressibility, are consistent with previously reported values for coarse grained Ti (c-Ti). The high pressure experiments on nc-Ti samples do no show any significant variation of the α → ω transition pressure under varying nonhydrostatic conditions. This is in sharp contrast to c-Ti, where a significant decrease in the α → ω transition pressure is observed under increasing nonhydrostatic conditions. As a result, this would indicate that the decrease in grain size in nano grained titanium makes the α → ω phase transition less sensitive to shear stresses as compared to bulk or c-Ti.
Authors:
 [1] ;  [1] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Alabama at Birmingham, Birmingham, AL (United States)
Publication Date:
OSTI Identifier:
1251166
Grant/Contract Number:
NA0002014
Type:
Accepted Manuscript
Journal Name:
Materials Research Express
Additional Journal Information:
Journal Volume: 1; Journal Issue: 3; Journal ID: ISSN 2053-1591
Publisher:
IOP Publishing
Research Org:
Univ. of Alabama at Birmingham, Birmingham, AL (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE high pressure; diamond anvil cell; titanium; electrical resistance