Molecular Dynamics Of The Melting And Sintering Of The Aluminum Nanoparticles

Micro/nano scale metal structures have great prospects application in micro/nano electromechanical systems,micro-nano sensors and other fields.The existing technologies are facing enormous challenges in the manufacture of complex micro-nano three-dimensional structures,especially when the ratio of the depth and width of the structures is high.Metal additive manufacturing technology is expected to break through this restriction.However,due to the poor dispersion of metal nanoparticles,large specific surface area,easy to be oxidized and lower melting point compared with macro-bulk materials,it is impossible to use the existing metal additive manufacturing technology.With the metal nanoparticles of various shapes and various materials are produced successfully,more and more people have studied the properties of metal nanoparticles.Because of the high cost of experiment,complex to design and difficult to operation,scholars all over the world widely used molecular dynamics simulation to study the size effect of metal nanoparticles,the sintering process and the exothermic self-sustaining reaction process of shell-core energetic materials under laser irradiation.The calculated results are in good agreement with the experimental data,which proves the reliability of the simulation analysis of molecular dynamics.At the same time,molecular dynamics can also observe phenomena which are difficult to be observed in the experiment,which has a guidance for the experiment.In this paper,the melting point of Al nanoparticles and the relationship between the melting point and its size were investigated by molecular dynamics.The effect of the existence of holes on the melting point of metal nanoparticles and the morphology change of holes in the melting process were also studied.The sintering process of two Al nanoparticles at room temperature and linear heating were also studied.The linear relationship between the melting point and the number of atoms contained in Al nanoparticles was found,and the mechanism of gradual melting of Al nanoparticles from the surface to the core during the melting process was found.Besides,the mechanism of bonding of two Al nanoparticles both in the room temperature and during the linear heating were also studied.It provides some reference for realizing micro-and nano-scale fabrication of metal additives.