Abstract: A series of simulation of the evolution of atom clusters in liquid Ni3Al alloy during rapid solidification have been performed under constant pressure and temperature by molecular dynamic simulation technique. TB(tightbinding) potential function has been adopted to describe the interaction between atoms. The structure parameters such as pair correlation function, bonded pairs and polyhedra clusters have been used to characterize the dependence of the type and number of clusters on temperature during rapid cooling process. The cluster structure could be visualized clearly through the conversion of atom coordinates obtained by simulation to threedimension graphical interface. The number of liquid Ni3Al clusters at the temperature of 2 000 K is small and all are made up of diicosahedron; however, it increases rapidly at the cooling rate of 4×1013 K•s－1, and finally,the icosahedra clusters occur at low temperature. The network consists of the icosahedra and diicosahedra clusters forming an amorphous system.

Key words: Molecular dynamic simulation, Rapid cooling process, Network of icosahedra clusters, Amorphous structure