Analysis of the effect of indenter deformation and presence of voids on silicon nanoindentation using molecular dynamics simulation

Document Type : Research Article

Authors

Faculty of Mechanical and Mechatronics Engineering, Shahrood University of Technology, Shahrood, Iran

Abstract

In the present study, a three-dimensional molecular dynamics simulation was carried out to investigate the nanoindentation of single-crystalline Silicon. The simulations were performed using the spherical shape rigid and non-rigid indenters. Subsequently, the effects of the substrate crystalline surfaces were investigated on the force-displacement curve of the indenter. The influence of the indentation force and depth were also studied on the hardness of the substrate. The findings of the simulation were then compared to the force-displacement curve published in the previous studies. The results of comparison between the rigid and non-rigid indenters revealed that the level of the force-displacement and hardness-displacement curves decrease by changing the assumption of rigid indenter to the non-rigid one. Moreover, the effects of void presence in silicon substrate (in various sizes at different positions) were investigated on the material hardness. According to the results, the larger the void and the closer it is to the surface of the workpiece, the more it can reduce the hardness. It was also concluded that the presence of voids in silicon substrate could reduce the hardness of the workpiece by 54%. Nevertheless, small voids near the surface may be eliminated during the nanoindentation process.

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