Al-centered icosahedral ordering in Cu46Zr46Al8 bulk metallic glass

Abstract

Icosahedral short-range order, of which Al atoms are caged in the center of icosahedra with Cu and Zr atoms being the vertices, has been evidenced in the Cu46Zr46Al8 glassy structure by ab initio molecular dynamics simulation. These Al-centered clusters distribute irregularly in the three-dimensional space and form a “backbone” structure of the Cu46Zr46Al8 glass alloy. It is suggested that this kind of local structural feature is attributed to the requirement of efficient dense packing and the chemical affinity between Zr–Zr, Zr–Al, and Cu–Zr atoms. Our calculated results are found to be in good agreement with the experimental data.