Molecular dynamics simulation-based study of single-crystal 3C-SiC nano-indentation with water film.

To elucidate the effect of water film on the behavior of single-crystal cubic silicon carbide (SiC) under nano-indentation, molecular dynamics (MD) simulations were employed in this work. Results showed that a pop-in event occurs during nano-indentation, which is jointly controlled by the atomic amorphization and dislocation nucleation. Compared to substrate without any water film, the depth of the incipient pop-in event of the substrate decreases with the thickness of water film, where the larger the water film thickness, the lower the depth. Therefore, it is concluded that the plasticity of the material is improved with the addition of water film. Besides, the number and length of dislocations of the substrate increase with the water film, and the migration of perfect dislocations in the [110] crystal direction of packed {111} plane also become homogenized. As the water film thickness increases, dislocation activities become more prevalent; however, the recovery of deformed crystal structure gets restrained. Owing to the increase of hydrostatic stress, the sub-surface damage of the substrate is exacerbated with the water film. In addition, the surface bulge of the substrate ascends with the water film. Finally, it is observed that the inhomogeneity of the surface bulge distribution is boosted with increasing water film thickness, while the adhesion of amorphous atoms to the diamond indenter is weakened. [ABSTRACT FROM AUTHOR]