RESUMO
This paper presents a set of general strategies for the analysis of structure in amorphous materials and a general approach to assessing the utility of any selected structural description. Two measures of structure are defined, "diversity" and "utility," and applied to two model glass forming binary atomic alloys, Cu50Zr50 and a Lennard-Jones A80B20 mixture. We show that the change in diversity associated with selecting Voronoi structures with high localization or low energy, while real, is too weak to support claims that specific structures are the prime cause of these local physical properties. In addition, a new structure-free measure of incipient crystal-like organization in mixtures is introduced, suitable for cases where the stable crystal is a compound structure.
RESUMO
The essential query about glass formation is how to understand the sheer temperature dependence of viscous dynamics of glass-forming liquids near the liquid-to-glass-transition temperature Tg. In this work, we report a universal scaling in the temperature-dependent viscous dynamics of metallic glasses (MGs) in the form of the Williams-Landel-Ferry equation on the basis of compiled data on the temperature-dependent viscosity and structural relaxation times of 89 MGs ever-reported in the past decades. Implications of this universal scaling are illustrated in the framework of the Adam-Gibbs relation, suggesting a universal vitrification mechanism in MGs mediated by configurational entropy wherein configurational entropy vanishes universally for all supercooled metallic liquids after a further decrease in temperature of â¼170.7 K (whereas with a relatively large error of ±150 K) below Tg. This result corroborates the thermodynamic origin of glass formation and suggests that MGs are an ideal research subject for understanding in depth the nature of glass transition for their relatively simple molecular structures.