Mg67Zn28Ca5 bulk metallic glass formation understood via close-packed icosahedron Zn2Mg11 eutectic cluster

Abstract Cluster characteristics of Mg 51 Zn 20 binary phase are analyzed using atomic density radial distribution method. Then icosahedron Zn 2 Mg 11 cluster, having the highest relative atomic density 2.45, is highlighted because of the most close-packed structure. Using cluster-plus-glue-atom model and Zn 2 Mg 11 cluster, eutectic composition Zn 28.1 Mg 71.9 of Mg–Zn binary system can be simply expressed as: [Zn 2 Mg 11 ] + (Zn 2.5 Mg 0.5 ). Therefore the most efficient packing icosahedron Zn 2 Mg 11 is also eutectic-related cluster. Finally, using general cluster formula [cluster](glue atoms) x (x = 1, 3), Mg-based Mg 67 Zn 28 Ca 5 bulk metallic glass may be deciphered via the most close-packed eutectic cluster Zn 2 Mg 11 as: [Zn 2 Mg 11 ] + (Zn 2 Ca 1 ).