Thermodynamic analysis of the V-H binary phase diagram

Shusuke Ukita, Hiroshi Ohtani, Mitsuhiro Hasebe

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

A thermodynamic analysis of the V-H binary system has been performed by combining first-principles calculations with the CALPHAD approach. In order to represent the order-disorder transition between the monoclinic ß1 and body-centered tetragonal ft phases arising from the ordering of H atoms located at the octahedral interstitial sites, a (V) 1/2(H,Va)1/4(H,Va)1/4-type three-sublattice model was applied. The formation energies of the δ-VH2 hydride phase and solid solution ß phases were calculated in the ground state using the Full-potential Linearized Augmented Plane Wave method, and the estimated values were introduced into a CALPHAD-type thermodynamic analysis, along with some experimental information on the phase boundaries and the hydrogen isotherms. The calculated phase diagram and hydrogen isotherms were in gooa agreement witn tnese experimental results.

Original languageEnglish
Pages (from-to)2528-2533
Number of pages6
JournalMaterials Transactions
Volume49
Issue number11
DOIs
Publication statusPublished - 2008 Nov 1
Externally publishedYes

Keywords

  • First-principles calculation
  • Hydrogen isotherms
  • Miscibility gap
  • Phase diagram
  • Thermodynamic analysis

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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