Accession Number:

ADA621027

Title:

Partial Coordination Numbers in Binary Metallic Glasses (Postprint)

Descriptive Note:

Journal article

Corporate Author:

AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE

Report Date:

2011-12-07

Pagination or Media Count:

17.0

Abstract:

A critical analysis of measured partial coordination numbers for binary metallic glasses as a function of composition shows a large scatter of -1.5 but clear trends. The current work uses two topological models to predict the influence of relative atomic size and concentration on partial coordination numbers. The equations for partial coordination numbers derived from these two models can reproduce measured data within experimental scatter, suggesting that chemical effects on local structure, although present, may be relatively small. Insights gained from these models show that structural site-filling rules are different for glasses with solute atoms that are smaller than solvent atoms and for glasses where solute atoms are larger than solvent atoms. Specifically, solutes may occupy both beta and gamma intercluster sites when the solute-to-solvent radius ratio R is less than 1.26, but only beta sites can be occupied by solutes when R 1.26. This distinction gives a simple topological explanation for the observed preference for binary metallic glasses with solutes smaller than solvent atoms. In addition to structure-specific equations, simplified phenomenological equations for partial coordination numbers are given as a convenience.

Subject Categories:

  • Metallurgy and Metallography
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE