Hydride formation in two-phase (Ti3Al + TiAl) titanium aluminides during cathodic charging and its dissociation

Akito Takasaki, Kozo Ojima, Youji Taneda

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14 Citations (Scopus)

Abstract

A (TiAl)Hx hydride which has a tetragonal crystal structure with lattice parameters a = 0.452 nm and c = 0.326 nm (c/a = 0.721) has been observed in Ti42Al, Ti45Al and Ti50Al (at.%) two-phase (Ti3Al (α2) + TiAl (γ)) titanium aluminides by cathodic charging in a 5% H2SO4 solution. Cracks or pits are also observed within the γ phase regions in the two-phase (α2 + γ) coexisting grains (such as lamellar grains) but not within the α2 phase or single γ grains. Weights of the samples decrease with increasing charging time owing to the crack or pit formation, and this is more drastic in the Ti-50Al alloy than in the Ti-42Al and Ti-45Al alloys. The hydride is thermally stable at temperatures up to about 550 K (277 °C) and dissociates completely at temperatures between 673 K (400 °C) and 723 K (450 °C).

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalJournal of Alloys and Compounds
Volume216
Issue number1
DOIs
Publication statusPublished - 1994 Dec

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Keywords

  • Cathodic charging
  • Hydride formation
  • Titanium aluminides

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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