Structural phase stability in nanocrystalline titanium to 161 GPa

Academic Article

Abstract

  • 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. 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.
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    Author List

  • Velisavljevic N; Jacobsen MK; Vohra YK
  • Volume

  • 1
  • Issue

  • 3