Investigations of the dynamic properties of the liquid phase of glassy Ca-Al alloys

Abstract

The Ashcroft pseudopotential is used in the evaluation of the partial potentials in the case of Ca₆₀Al₄₀ glass melts. These potentials are found to give minima at the principal peaks of the partial radial distribution functions. The partial structure factors are evaluated and compared with literature values. From the partial potentials and partial structure factors the corresponding effective potential and total structure factor are evaluated. The effective radial distribution function is calculated from the total structure factor. These effective quantities are used in the evaluation of phonon frequencies through Takeno and Goda's equations. It is found as predicted by Bhatia and Singh that the structure factor maximum is around the first minimum of the longitudinal phonon frequency. From the slopes of the phonon frequencies the elastic constants are evaluated. The elastic constants are also evaluated from Schofield's I₁ and I₂ integrals. Further from Kirkwood-Buff's equation using the partial direct correlation functions in the long-wave limit the compressibility is evaluated and the elastic constant C₁₁ is calculated. There is a good interconsistency in the computed values of the elastic constants.