The Theoretical Research Of Micro-structural And Thermal Properties Of Co And Its Alloys

In recent years, Clusters have gained much attention for its special physical and chemical properties. With the in-depth study and the development of technology, the geometric structure, thermal properties and other properties of the elemental metal clusters and alloys clusters, no matter experiment or theory, had a more comprehensive understanding. The study found that the alloys clusters in bio-medical, chemical catalysis, magnetism material has a broad application prospect. By means of adjusting the composition, proportion, and clusters size to change its physical and chemical properties for getting the new material. At present, the research on micro-structure and thermal properties of the clusters is one of the important subjects of condensed matter physics, and the meaning of clusters of scientific research is that to connect the nature of the microscopic structure and macroscopic material.In this paper, the Co and its alloys clusters are simulated during the cooling process by using molecular dynamics with the embedded-atom method. Taken advantage of Radial distribution function, HA index, bond order parameter and so on to analysis the structural data, and get some conclusions as follows:1. The simulated result of Co₁₀₁₇₉ cluster shows that the micro-structure transformation ranges from 1300 K to 1200 K, and the freezing point is 1200 K. The final structure of cluster mainly has shows the structural characteristics of fcc and hcp.2. In the simulation process of Co₁₄₇Ni₄₁₄ cluster, finds that the segregation phenomenon has happened in the cluster, what the reason is that the different atom type has different surface energy, and the cluster form the stable core-shell structure. By analyzing the curve of potential energy and heat capacity, get the freezing point of cluster is 1167 K. The structure of cluster has the characteristics of hcp and fcc.3. The influence of cluster concentration on the frozen structures of?Co Al?1415 cluster with different concentrations. It is found that the concentration effect on the frozen structure is obviously. The frozen structure of?Co Al?1415 clusters with 100%⁷0% Co concentrations form hcp structures. The?Co Al?1415 clusters with 30%¹0% Co concentrations have the icosahedron and defect icosahedral structural characters. The?Co Al?1415 clusters with 60%, 40% and 10% Co concentrations form a variety of structure characters.