Heredity of clusters in the rapidly cooling processes of Al-doped Zr₅₀Cu₅₀ melts and its correlation with the glass-forming ability

The heredity of clusters in rapidly cooled (Zr₅₀Cu₅₀)_100-xAl_x melts and its correlation with glass-forming ability (GFA) are studied via molecular dynamics simulations. Pair distribution function and the largest standard cluster (LSC) are adopted to characterize the local atomic structures in the (Zr₅₀Cu₅₀)_100-xAl_x systems. The 12/555 icosahedra and their medium-range order (IMRO) play an important role in forming (Zr₅₀Cu₅₀)_100-xAl_x metallic glasses (MGs). The fraction of 12/555, the number of IMRO, and the maximum size of IMRO in MGs increase significantly with increasing x. A tracking study further reveals that the configuration heredity of icosahedral clusters starts from supercooled liquids. No direct correlation exists between the GFA and the onset temperature of continuous or stated heredity. Instead, a larger hereditary supercooled degree of icosahedra matches with better GFA of Al-doped Zr₅₀Cu₅₀ alloys.