SiC ceramics is very promising to be widely applied due to the excellent physical and chemical properties.However, the very difficult process of SiC ceramics hinders its application. In this paper, the nano-cutting of SiC ceramics is simulated based on molecular dynamics. The influences of the tool rake and cutting depth on the cutting force, the kinetic energy and potential are analyzed. The results show that the cutting force, system kinetic energy and potential energy increase firstly,reach the maximum, and then decrease in the process; with the increase of the tool rake, the cutting force and the kinetic energy decrease; with the increase of the cutting depth, the cutting force increases, and the kinetic energy and the potential energy decreases. These results are very helpful to understanding the process mechanism of SiC ceramics and increasing its process efficiency

A 3D model of molecular dynamics for nanoceramic SiC is adopted to simulate the hot pressing sintering and preparation process of SiC, and mechanical properties such as density, hardness and elastic modulus are calculated. Finite element model of indentation is established based on the mechanical performance parameters from MD simulation. Conical indenter is adopted in indentation simulation. The FEM simulation results show that: Maximum equivalent stress appears at the place of indenter tip, and equivalent stress curves are appeared hemispherical. As indentation depth increases, the stress increased. As the distance of away from the indenter increases, the displacement in equivalent displacement nephogram gradually decreased until zero. During unloading process, elastic restitution is occurred. The elastic restitution in the area of below the indenter is obviously. Residual stress in the center of indentation is maximal after unloading.

With the development of Micro-electro-mechanical systems (MEMS) and Nano-electro-mechanical systems (NEMS), dimension of their parts is required to nanometer scale, and the characteristics of machined-surface of nano-scale parts affect strongly its application. Surface relaxation plays an important role to the characteristics of the machined-surface. In this paper, machined-surface of monocrystal copper used as the specimen of surface relaxation, and its surface relaxation process is simulated. The influences of surface relaxation on surface energy, atom array, surface roughness, surfaces hardness and surface residual stress of the monocrystal copper are analyzed. Results show that surface energy and surface hardness decrease due to relaxation; work-hardening can’t be completely eliminated by the relaxation; compression residual stress of the machined surface is changed gradually to tensile stress during the relaxation. These research results are very helpful to the application of nano-machined parts.

Silicon nitride nanoscale cutting model was established by molecular dynamics simulation, and interactions force between atoms of work-piece was calculated by Tersoff potential function. Through the three-dimensional simulation of silicon nitride nanocutting process, the changes of cutting force, kinetic energy and potential energy in the nanoscale cutting process, and the effects of cutting thickness and cutting speed on the entire cutting process were analyzed. The results showed that the kinetic energy, potential energy and cuting force increased along with the cutting thickness increasing, both kinetic energy and potential energy decreased with cutting speed increasing.

SiC ceramics have been widely used in a variety of areas due to the excellent physical and chemical properties. However, the process of SiC ceramics is difficult and high-cost, molecular simulation is an effective and feasible method to study the nano-process of SiC ceramics. In this paper, a molecular model is presented to simulate the stress and energy in the nano-cutting of SiC ceramics. The influences of the cutting depth and cutting speed on the kinetic energy and potential are analyzed. The results show that potential energy increases with the decrease of the cutting depth. Kinetic energy increases with the increase of the cutting speed. The results are very helpful for improvement the level of ultra-precision processing and nano-processing of brittle ceramics.