Molecular Dynamics Analysis of 6H-SiC Subsurface Damage by Nanofriction

DL Yu and HL Zhang and XY Feng and DH Liao and NX Wu, ACS OMEGA, 7, 18168-18178 (2022).

DOI: 10.1021/acsomega.2c02115

To investigate the subsurface damage of 6H-SiC nanofriction, this paper uses molecular dynamics analysis to analyze the loading process of friction 6H-SiC surfaces, thus providing an in-depth analysis of the formation mechanism of subsurface damage from microscopic crystal structure deformation characteristics. This paper constructs a diamond friction 6H-SiC nanomodel, combining the radial distribution function, dislocation extraction method, and diamond identification method with experimental analysis to verify the dislocation evolution process, stress distribution, and crack extension to investigate the subsurface damage mechanism. During the friction process, the kinetic and potential energies as well as the temperature of the 6H-SiC workpiece basically tend to rise, accompanied by the generation of dislocated lumps and cracks on the sides of the 6H-SiC workpiece. The stresses generated by friction during the plastic deformation phase lead to dislocations in the vicinity of the diamond tip friction, and the process of dislocation nucleation expansion is accompanied by energy exchange. Dislocation formation is found to be the basis for crack generation, and cracks and peeled blocks constitute the subsurface damage of 6H-SiC workpieces by diamond identification methods. Friction experiments validate microscopic crystal changes against macroscopic crack generation, which complements the analysis of the damage mechanism of the simulated 6H-sic nanofriction subsurface.

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