Nanoindentation Models With Realistic AFM Tip Geometries

In this paper, a three-dimensional computational model for Atomic Force Microscopy (AFM) based nanoindentation processes is being developed. Molecular Dynamics (MD) and Finite Element (FE) techniques are used to model and simulate mechanical indentation at the nanoscale. The correlation between the indentation conditions, including applied force and tip radius, and defect mechanism in substrate is investigated. The tip geometries used in the model are the same as those used in the experiments. The MD simulations of nanoindentation process are performed on different crystal orientations of single-crystal gold substrate, Au(100), Au(110), and Au(111). In MD simulation, the material deformation is 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. In addition to the modeling, an AFM is used to conduct actual indentation at the nanoscale, and provide measurements to which the simulation predictions are compared.