Influence of clusters in melt on the subsequent glass-formation and crystallization of Fe-Si-B metallic glasses

The liquid structure of seven representative Fe-Si-B alloys has been investigated by ab initio molecular dynamics simulation focusing on the role of clusters in terms of glass-forming ability (GFA) and crystallization. It is demonstrated that the type of primary phase precipitated from amorphous state under heat treatment is determined by the relative fraction and role of various clusters in melt. The alloy melt shows higher stability and resultantly larger GFA when there is no dominant cluster or several clusters coexist, which explains the different GFAs and crystallization processes at various ratios of Si and B in the Fe-Si-B system. The close correlation among clusters, crystalline phase and GFA is also studied.