Local Topology vs. Atomic-Level Stresses as a Measure of Disorder: Correlating Structural Indicators for Metallic Glasses

Abstract

This brief overview presents a critical assessment of the choice of structural parameters that may be used to describe the degree of local order/disorder in metallic glasses (MGs) and to establish the relationship between the amorphous structure and the properties of an MG. By summarizing our own quantitative analysis of representative MG models, we compare, and relate to one another, several measures of structural disorder in amorphous alloys, including the topology of quasi-equivalent clusters, the concept of free volume, and the atomic-level stresses. The model systems used for demonstrating the correlations are characterized by two different and prototypical types of short-range order (SRO): a Cu64Zr36 MG exhibiting pronounced icosahedral SRO, and a Pd82Si18 MG representative of a metal–metalloid system, with solute-centered tri-capped trigonal prisms as the dominant local motif. Also outlined are some ideas in terms of the relationship between the glass structures and properties, including the challenges in correlating the local structures with the propensity for relaxation and shear transformations.