Molecular Dynamics Simulation Of Nano-film Deposition And Mechanical Behavior Of Metal Oxidation Process

Molecular dynamics simulation is a method used to calculate the balance and transport properties of a classical multibody system. It is rapidly developed in recent years. As a powerful method of nano scale simulation, it is able to simulate the real process of the movement of atoms in solid and understand the mechanism of the evolution of macro-process in depth. It is an important means to evaluate surface structure and dynamics in diffusion.It is a powerful tool to study condensation phenomenon such as solid, liquid structure, surface-interface properties and relaxation processes. It has been widely adopted in the calculation of thermodynamic and kinetic properties, as well as the structure of the system. It has a wide range of practical exercises and attractiveness point of view.The growth of Al film on Cu surface and the Al metal oxidation process have been simulated under three-dimensional molecular dynamics by open source software Lammps in this paper. The growth mechanism of Al film on Cu(001) surface, the influence of depositing atom energy to Al film growth, and the influence of orientation and temperature to the mechanical behavior of single crystal aluminum oxidation process are respectively studied in detail. The main conclusions were as follows:(1) The upgraded module of deposit have been written and embedded by learning and debugging the open source C++code. Maintain a constant number of atoms can be achieved. The feasibility and effectiveness of the simulation can also be determined.(2) Energetic atom deposition simulation results in Al thin film Cu (001) surface shows that: The growth of the film structure and the choice of the substrate material have a close relationship. Depositing atoms in the early stages of the deposition process, the thin film structure will be first match the growth of the crystal structure of the substrate atoms. With the increasing thickness of the film structure, the film will gradually shift the growth of a crystal plane direction.(3) The degree of crystallization and the energy deposited with a thin film growth structure have a close relationship. When the incident energy is low, the degree of crystallization of the thin film structure is good. With the increase in the amount of incident energy, the structure of a metal thin film is not crystallized. At the same time, there will be base atoms into the interior of the film, forming hybrid on the deposition film hybrid. The method of high temperature degradation can effectively eliminate the defects of the deposited thin film crystal structure.(4) The molecular dynamics simulation of the Al oxidation process can be achieved by reax reaction force field. The simulation results of Al metal oxidation indicate that:Aluminum oxidation film growth mechanism does not depend on direction in the crystal. It means that the initial oxidation of the initial process in different orientation is almost the same. However, due to the different surface density of the crystallographic orientation,the final thickness of the oxidation film is different. The thickness increases with the increase of areal density, respectively1.3nm,1.36nm,1.53nm. The oxidation film growth stress of different orientation is also increasing with areal density.(5) With increasing temperature, the oxidation rate of aluminum is gradually increased under the same crystal conditions. The limit thickness of the oxide film is also increasing with increasing temperature, respectively1.36nm,1.4nm,1.5nm. The faster the oxidation rate, the greater the peak stress of the oxide film.