Cluster Formula Describing Alloy Phase And Applying In Cu-Ti Metallic Glasses System

The composition designing of metallic glasses is based on empirical criteria to find the best composition.As a new description method,clusters are applyed in alloy phase in terms of composition and structure,and are widely used in the study of alloy phases and metallic glasses.Recent studies have shown that the ideal metallic glasses satisfied cluster-plus-glue-atom model,that is,the structure of bulk metallic glass is an isolated cluster plus glue atoms.We apply this method to describe the macroscopic composition and microstructure of alloy phase and metallic glasses.The research contents and research achievements of this paper are as follows:1.Since the nearest-shell atoms in the alloy phase are often not strictly located on the same shell,the precise definition of clusters becomes the key issue to be solved in this paper.In this paper,we proposed two definitions of Miracle's model and atomic density radial distribution illustrated in B-Co-Si system alloy phase.The comparison of the calculation results shows that defining the closed-packed cluter using atomic density radial distribution method is more accurate and convenient.2.Applying cluster formula in B-Co-Si,Al-Ni-Zr and Cu-Ti alloy phases,the cluster atoms are not isolated in the alloy phase,but are interconnected by the sharing atoms in the alloy phase.After sharing,the cluster is reduced to an effective cluster,alloy phase can be expressed as[effective cluster]?glue atom?.This method is used to analyze the structure of all the clusters in the B-Co-Si alloy phase,which shows the rationality and practicability of the method.3.Alloy phase has several non-equivalent atomic occupations,so the alloy phase has a plurality of cluster formula to represent its structure and composition,in order to select the most appropriate cluster representative of alloy phase local atomic structure characteristics,we need to choose the principle cluster.In this paper,the structural characteristics?dense packed?and the arrangement of clusters?sharing degree?are considered to choose cluster.4.Cu-Ti alloy phase was analyzed and the principle cluster was selected.Principle cluster was used to design Cu₅₀Ti₅₀,Cu₅₀Ti₄₀Ni₁₀,Cu₅₅Ti₂₉Zr₁₆ and Cu_52.55Ti_30.05Zr_11.4Ni₆ metallic glasses with good properties,which provided new ideas for the composition designing of metallic glasses.