Ab initio molecular dynamics simulation of the atom packing and density of Al-Ni amorphous alloys  

作　　者：YU ChunYan1, HUI XiDong1, CHEN XiaoHua1, LIU XingJun1, LIN DeYe1, LIU ZiKui2 & CHEN GuoLiang1 1 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China 2 Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802, USA 

出　　处：《Science China(Technological Sciences)》2010年第12期3175-3182,共8页中国科学（技术科学英文版）

基　　金：supported by the National Basic Research Program of China ("973" Program)(Grant No. 2007CB613901);the National Natural Science Foundation of China (Grant Nos. 50871013, 50901006)

摘　　要：Al-Ni alloys have better glass forming ability (GFA) than other Al-based alloys. However, the relationship among the atomic arrangement, glass transition, packing density and composition hasn’t been systematically studied. In this paper the ab initio molecular dynamics simulation (AIMD) was performed on the atom packing and density of AlxNi100-x (x=80, 83, 85, 86, 87 and 90) alloys. The pair correlation function and Voronoi tessellation indicated that there are obvious topological and chemical short-range orders in these alloys. The topological structure consists of Al-centered icosahedra like and Ni-centered tri-capped trigonal prism (TTP) like polyhedra. There is strong chemical short-range ordering between Al and Ni atoms indicated by the bond-length of Al-Ni pair shorter than the sum of the radii of Al and Ni atoms, which increases with the increasing of Ni content. It is shown that the densities of amorphous alloys don’t agree with the linear law with a peak at x=85. Based on the features of the structure and density, it is concluded that Al-Ni alloys at x=84–86 have high GFA, which can be extended to multi-component Al-based alloys.Al-Ni alloys have better glass forming ability (GFA) than other Al-based alloys. However, the relationship among the atomic arrangement, glass transition, packing density and composition hasn’t been systematically studied. In this paper the ab initio molecular dynamics simulation (AIMD) was performed on the atom packing and density of AlxNi100-x (x=80, 83, 85, 86, 87 and 90) alloys. The pair correlation function and Voronoi tessellation indicated that there are obvious topological and chemical short-range orders in these alloys. The topological structure consists of Al-centered icosahedra like and Ni-centered tri-capped trigonal prism (TTP) like polyhedra. There is strong chemical short-range ordering between Al and Ni atoms indicated by the bond-length of Al-Ni pair shorter than the sum of the radii of Al and Ni atoms, which increases with the increasing of Ni content. It is shown that the densities of amorphous alloys don’t agree with the linear law with a peak at x=85. Based on the features of the structure and density, it is concluded that Al-Ni alloys at x=84–86 have high GFA, which can be extended to multi-component Al-based alloys.

关 键 词：AIMD AL-NI alloys DENSITY SHORT-RANGE order chemical SHORT-RANGE order 

分 类 号：TG146.21[一般工业技术—材料科学与工程]