Molecular dynamics simulation of laser-induced graphitization of CVD diamond

Diamond material has been widely used in the manufacture of high performance optical components due to its excellent mechanical and optical properties. CVD diamond can be used as inertial confinement fusion (ICF) target, X-ray lens of the fourth-generation light source, and infrared window, etc. In order to achieve high quality manufacturing of CVD diamond components, laser-induced graphitization technology can be used to improve the machinability of CVD diamond surface. In this paper, the surface generation mechanism of CVD diamond under laser irradiation were studied by molecular dynamics (MD) simulation. Firstly, a model of polycrystalline CVD diamond under laser ablation was established to reveal removal and evolution of surface materials at the atomic level. The MD simulation results with different grain sizes under laser irradiation were compared, and the influence of grain boundaries and grain size on laser graphitization was determined. Finally, the laser machining processes of CVD diamond were simulated under different laser spot diameters, and the influence of laser area on the graphitization degree of CVD diamond surface was analyzed.