Vibrational dynamics of non-crystalline glassy alloys

Abstract

The vibrational dynamics of three Ca-based non-crystalline alloys viz. Ca₇₀Mg₃₀, Ca₇₀Zn₃₀ and Ca₆₀Al₄₀ have been studied at room temperature in terms of the phonon eigen frequencies of longitudinal and transverse modes, employing three theoretical formulations given by Hubbard-Beeby (HB), Takeno-Goda (TG) and Bhatia-Singh (BS). Five local field correction functions viz. Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used for the first time in the present investigation to study the screening influence on the aforesaid properties. The pseudo-alloy-atom (PAA) model is applied for the first time instead of Vegard s Law. Long wavelength limits of the phonon modes are used to investigate the elastic and thermal properties of the system. The low temperature specific heat is also calculated from the elastic limit of the phonon dispersion curves (PDCs). The present findings of the PDCs of Ca₇₀Mg₃₀ glass are found in fair agreement with available theoretical and experimental data.

Keywords

pair potential, metallic glasses, elasticity, phonon dispersion curves (PDCs), thermodynamic properties, elastic properties