Atomic Level Structure in Multicomponent Bulk Metallic Glass

The atomic-level structure of a representative ternary Cu-Zr-Al bulk metallic glass (BMG) has been resolved. Cu- (and Al-) centered icosahedral clusters are identified as the basic local structural motifs. Compared with the Cu-Zr base binary, a small percentage of Al in the ternary BMG leads to dramatically increased population of full icosahedra and their spatial connectivity. The stabilizing effect of Al is not merely topological, but also has its origin in the electronic interactions and bond shortening.