The relationship between the spatial heterogeneity of the microstructure and the glass-forming ability of Al85Ni10Fe5 metallic glass

Abstract Spatial heterogeneity of the microstructure is an inherent characteristic of metallic glasses, which significantly influences their glass-forming ability (GFA) and thermal stability. In this study, we employ molecular dynamics simulations to investigate the evolution of spatial heterogeneity in the microstructure of the Al85Ni10Fe5 alloy during the glass transition process. Our results reveal that the Al85Ni10Fe5 metallic glass exhibits much higher spatial heterogeneity in terms of five-fold symmetry compared to the Al85Ni15 alloy. Furthermore, the spatial heterogeneity of the five-fold symmetry increases more dramatically during the cooling process in the Al85Ni10Fe5 system, while the spatial heterogeneity of the four-fold symmetry, which is associated with the crystalline phase, is lower in Al85Ni10Fe5 than in Al85Ni15. Interestingly, the spatial heterogeneity of the four-fold symmetry in Al85Ni10Fe5 first increases with decreasing temperature and then rapidly decreases near the glass transition temperature. These structural characteristics, which benefit the formation of higher five-fold symmetric clusters and their spatial aggregation, thus suppressing the growth of the crystalline structure in the liquid, contribute to the larger GFA of the Al85Ni10Fe5 alloy compared to the Al85Ni15 alloy. Our findings provide valuable insights into understanding the glass-forming ability of Al-based metallic glasses.