Study And Simulation Of Atoms Loyalty Model In The Liquid Microstructure

As one of the three major forms of matter,liquid exists widely in all aspects of life,and the nature and evolution of liquid structure has always been a hot issue.At present,random packing,highly disordered crystals and free volume models are usually used to explain the structure of liquids.The above models successfully describe the long-range disorder and short-range ordering law in the liquid structure.Recently,these models used to study liquids have also been used to explain the amorphous structure of metallic glasses.However,whether short-range or medium-range ordering,the model based on random dense packing only describes the instantaneous state of liquid,and the results do not show the fluctuation of atomic clusters in liquid state.All phase transitions,including liquid-solid phase transitions and liquid-liquid phase transitions,are heterogeneous processes varying with time,so it is necessary to consider the motion of atoms in liquids.In this paper,a new microstructural model named atomic loyalty model is designed.Molecular dynamics simulation was used to reveal the transient characteristics of atoms in liquid structure and the transition of micro cluster structure in liquid state,considering the coordination of atoms at different time.Using this model,we can more intuitively understand and describe the micro-structure clusters in liquid state and the transformation process between clusters.It is helpful to understand the transition between liquid and liquid and the transformation between liquid and solid,and thus to visually understand the transition process from liquid to amorphous state.Molecular dynamics simulation was used to validate the model by melting of copper,crystallization of zirconium and glass curing process of copper-zirconium binary alloy.The simulation results are in good agreement with previous conclusions.Finally,we use the atomic loyalty model to explain the phenomenon of liquid-liquid phase transition.The results show that liquid-liquid phase transition is an inevitable phenomenon in the process from liquid cooling to solid state.It is characterized by the appearance of loyal atoms in liquid atoms,which do not change with time.When all atoms have loyal atoms,the microscopic structure of liquid will change and liquid-liquid phase transition will take place.This model can provide a simple and practical simulation method for the future study of the amorphous formation ability of liquid-glass transition.