A generalized polytetrahedral cluster approach to partial coordination numbers in binary metallic glasses

AYKOL M., MEKHRABOV A., AKDENİZ M. V.

PHILOSOPHICAL MAGAZINE, vol.91, no.22, pp.2985-3005, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 91 Issue: 22
  • Publication Date: 2011
  • Doi Number: 10.1080/14786435.2011.558031
  • Journal Name: PHILOSOPHICAL MAGAZINE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.2985-3005
  • Middle East Technical University Affiliated: Yes

Abstract

Partial coordination numbers (CNs) play a substantial role in description of hetero-coordinated local structure and related short-range order in metallic glasses. By defining a polytetrahedral aggregation for solute-solvent type atomic clusters, which retains cluster sphericity, high solute-solvent and solvent-solvent CNs, a preliminary model is developed to estimate the CN of a solute atom within a non-isolated cluster embedded in the glassy environment. Employing the result, a generalized quasi-hard sphere model is constructed by defining intra-and inter-cluster correlations, which can yield significantly close values to experimentally derived partial CNs in a great many metallic glass systems, such as Fe-B, Ni-B, Ni-P, Co-P, Pd-Si, Al-Y, Co-Zr, Co-Ti, Ni-Ti, Zr-Ni, Zr-Pd, Zr-Pt and Cu-Zr. The approach allows evaluation of a complete set of partial CNs in a given binary system as a function of atomic radii and composition.