Study on the influence of anisotropy of ZnGeP2 single crystal on its surface cutting quality

Improving the surface quality of ZnGeP2 is an important way to expand its application range. The anisotropy of the ZnGeP2 crystal affects the surface quality after material removal. Through the nano-indentation experiment of ZnGeP2 crystal, the anisotropy hardness and brittle plastic transformation depth were observed. The influence of anisotropy on the cutting process was verified by molecular dynamics simulation and diamond tool turning. The nano-scratch test was carried out on the surface of ZnGeP2, to analyze the range of plastic regions at different angles in combination with the microscopic morphology changes. Finally, cutting experiments in different directions of ZnGeP2 was carried out by diamond fly-cutting machine tool. The simulation and experiment results showed that the ZnGeP2 crystal is anisotropic and with the smallest cutting force along the [100] direction. During the fly-cutting process, when the cutting direction along 0 degrees and 180 degrees, the surface roughness value Sa could reach to 9.988 nm, the surface quality was higher than that in the other cutting directions.