Investigation of the structure of β-tantalum

Abstract

The local structure of β-tantalum was investigated by comparing experimental extended X-ray absorption fine structure (EXAFS) measurements with calculated spectra of proposed models. Four possible structure candidates were examined: a β-Uranium based structure, a distorted A15 structure, a bcc-Ta based superlattice structure with N interstitials and a simple hcp structure. The local structural measurements were found to be consistent with the β-Uranium based model containing 30 atoms per unit cell and having the space group P42/mnm. The thermal effect analysis on X-ray diffraction and EXAFS spectra, which reveals that β-Ta is highly disordered, agrees with the low symmetry and anisotropic system of the β-U model. © 2003 Elsevier Science B.V. All rights reserved.