A molecular dynamics simulation study of solid-like and liquid-like networks in Zr46Cu46Al8 metallic glass

• We simulate Zr46Cu46Al8 metallic glasses by using molecular dynamics.
• Atoms with high and low degrees of fivefold symmetry respectively form solid and liquid-like networks.
• Atomic level stress is correlated with short to medium-range structure.
• The predicted solid and liquid-like regions exhibit different mechanical properties.

Classic molecular dynamics simulations were carried out to monitor the solid and liquid-like regions in Zr46Cu46Al8 metallic glass. Based on Voronoi tessellation analysis, this work illustrates that the medium range networks are related to the local fivefold symmetry. Not only atoms with high degree of local fivefold symmetry (Kasper polyhedra) form percolated networks, but also atoms with low degree of fivefold symmetry tend to build up interconnected superclusters. In addition, strong avoidance is observed between these two kinds of atoms. Such spatial heterogeneity is analyzed in terms of its dependence on atomic level stress. Starting from the networks formed by these two kinds of atoms, they are respectively assumed to be solid and liquid-like regions. Our quantitative monitoring of von Mises shear strain suggests that liquid-like networks are fertile sites for plastic deformation, while the backbones formed by atoms with high degree of fivefold symmetry are resistant to shear events. Such investigations on solid and liquid-like regions have implications for the structural and mechanical heterogeneity reported in metallic glasses.