Rapeepan Promyoo, Hazim El-Mounayri and Kody Varahramyan, Indiana University Purdue University Indianapolis, USA

In this paper, a developed three-dimensional Molecular Dynamics (MD) model for AFM-based nanomachining is applied to study mechanical indentation and scratching at the nanoscale. The correlation between the machining conditions, including applied force, depth, tip speed, and defect mechanism in substrate/workpiece is investigeted. The simulations of nanoscratching process are performed on different crystal orientations of single-crystal gold substrate, Au(100), Au(110), and Au(111). The material deformation and deformed geometry are extracted from the final locations of atoms, which are displaced by the rigid indenter. The simulation also allows for the prediction of forces at the interface between the indenter and substrate. Material properties including modulus of elasticity and hardness are estimated. It is found that properties vary significantly at the nanoscale. In addition to the modeling, an AFM is used to conduct actual indentation and scratching at the nanoscale, and provide measurements to which the MD simulation predictions are compared. Due to computational time limitation, the predicted forces obtained from MD simulation only compares well qualitatively with the experimental results.

AFM-based Nanomachining, Molecular Dynamics (MD), Nanoindentation, Nanoscratching, Simulation