Simulated Cu–Zr glassy alloys: the impact of composition on icosahedral order

Abstract

The structural properties of the simulated Cu_αZr_1-α glassy alloys are studied in the wide range of the copper concentration to clarify the impact of the composition on the number density of the icosahedral clusters. Both bond orientational order parameters and Voronoi tessellation methods are used to identify these clusters. Our analysis shows that abundance of the icosahedral clusters and the chemical composition of these clusters are essentially nonmonotonic versus and demonstrate local extrema. That qualitatively explains the existence of pinpoint compositions of high glass-forming ability observing in Cu Zr alloys. Finally, it has been shown that Voronoi method overestimates drastically the abundance of the icosahedral clusters in comparison with the bond orientational order parameters one.