Abstract

The indentation response of Ni thin films of thicknesses in the nano scale was studied using molecular dynamics simulations with embedded atom method (EAM) interatomic potentials. A series of simulations were performed in films in the [111] orientation with thicknesses varying from 4 to 12.8 nm. The study included both single crystal films and films containing low angle grain boundaries perpendicular to the film surface. The simulation results for single crystal films show that as film thickness decreases larger forces are required for similar indentation depths but the contact stress necessary to emit the first dislocation under the indenter is nearly independent of film thickness. The low angle grain boundaries can act as dislocation sources under indentation. The mechanism of preferred dislocation emission from these boundaries operates at stresses that are lower as the film thickness increases and is not active for the thinnest films tested. These results are interpreted in terms of a simple model.

 

Biography

Arun K. Nair has obtained his Bachelors degree in civil engineering from Mahatma Gandhi University, India and then obtained an M.S in civil engineering from Colorado State University. He is currently pursuing his Ph.D in ESM department under Dr.Ronald D. Kriz (ESM) and Dr.Diana Farkas (MSE).