Silicon Nitride Nano Cutting Simulation By Molecular Dynamics

Ceramic materials because of their excellent physical and chemical properties, such as high hardness, high temperature resistance, wear resistance, corrosion resistance and light weight, good thermal performance, are widely used in various fields. But due to its brittleness, low reliability, poor strength, its application is greatly restricted. In the process of machining experiment, experiment becomes very difficult and time-consuming. The requirements of experiment on ultra-precision machine tools, resolution of detecting instrument, cutting condition, cutting tool and its geometry shape were extremely harsh, therefore, to the present experimental conditions, using experimental method to study the mechanism of nanometer processing was very difficult. With the development of computer technology, molecular dynamics (MD) simulation can solve these problems, it is a powerful method of computer simulation. It can change the corresponding parameters according to the need in the simulation, such as cutting conditions, the geometry of the tool and material properties of the workpiece. It explored macroscopic characteristics of experimental process from the microscopic details, be helpful for correct interpretation of nano machining mechanism.Firstly, the development status of applying molecular dynamics simulation to study nanometer processing at home and abroad and the principle of molecular dynamics theory were described in detail for the topic. Secondly, according to the Visual C++6.0as a platform, using C++to programme simulation program, establishing molecular dynamics simulation model of silicon nitride nanoscale cutting. Using the VMD visualization technology has been the instantaneous image of the cutting process, cutting condition was observed in the whole cutting process.This paper established molecular dynamics model of the silicon nitride nanoscale cutting, the Tersoff potential function was calculated atomic interactions, simulating machining process of silicon nitride ceramic materials, and making a comprehensive analysis of nanoscale cutting process, the influence of the cutting depth, cutting speed, cutting rake angle on nanometric cutting process were studied respectively from the change rules of cutting force, cutting temperature and the evolution of system energy, and formation mechanism of machined surface was studied in the process. Simulation results showed that cutting force, cutting temperature and energy will be occur severely concussion because of the changes of the lattice structure in the nanoscale cutting process; cutting force, kinetic energy, potential energy and temperature were increased with the cutting thickness increasing. It can be appropriate to improve the simulation speed to save simulation time in the nanometric cutting process; improving the quality of finished surface by increasing the rake angle to reduce the surface roughness. The influence of cutting parameters on cutting process was studied in this paper, making detailed analysis for the nanoscale machining process. Lay a good theoretical basis for ceramic materials processing, and have certain guiding significance for rising level of ceramic materials nanoscale processing.