Simulation and experimental study on limited cutting and heat effect of silicon carbide

As a typical third-generation semiconductor material, silicon carbide (SiC) presents outstanding properties in terms of the bandgap width, disruptive voltage strength, thermal conductivity and so on. However, there are still technical difficulties in acquiring the nondestructive surface with an optical quality, which seriously constrained the application and development of SiC functional devices. Therefore, in this paper, the material removal mechanism of SiC was firstly investigated according to the MD simulation results. Then, nanocutting experiments were conducted under the vacuum environment of the scanning electron microscope, where the transient behavior of material removal could be observed online with a high resolution, so that the simulation results can be effectively verified. From the simulated and experimental results, it was found that under the research range of parameters, the limited removal thickness (LRT) of SiC decreased with an increase in cutting speed, while the cutting depth had little effect on the LRT. Besides, the polycrystalline SiC presented a smaller LRT compared with the monocrystalline SiC. Therefore, it was advantageous to enhance the machined surface quality and improve the surface integrity with regard to polycrystalline SiC. The cutting temperature increased with an increase in cutting speed during the nanocutting, and a higher cutting speed can prolong the time for the workpiece tem-perature to stabilize. The findings of this study are able to provide a theoretical basis for the improvement of ultraprecision machining technology especially for hard-brittle and hard-to-process materials.