The influence of drilling speed on the evolution mechanism of subsurface defects in single crystal 3C-SiC in molecular dynamics

To investigate the effect of drilling speed on the molecular dynamics and subsurface defect evolution mechanism of 3C-SiC single crystals, a coupled molecular dynamic model for drilling is established. A multi-scale molecular dynamic potential energy function is established by combining the variational potential energy between C–Si bonds, based on this, the mechanical response coupling model is developed. By analyzing factors such as molecular dynamics temperature and periodic boundaries, a molecular dynamic differential ensemble environment drilling is constructed to achieve a constant temperature and pressure simulation environment for the evolution of sub-surface defects in single crystal 3C-SiC molecular dynamics. At drilling velocities of 30 m/s, 60 m/s, and 90 m/s, dislocation exchange occurs that the load stability is affected. When the drilling reaches a certain depth, the load tends to be constant, with values of 5.22 × 10⁴ eV/Å, 3.36 × 10⁴ eV/Å, and 0.58 × 10⁴ eV/Å. Load changes during differential drilling impact single crystal 3C-SiC irreversibly. By comparing and analyzing the simulation results at different drilling speeds, it offers ideas for understanding the material response of single crystal 3C-SiC during high-speed machining from the point of view of dislocation energy changes.