Quasicontinuum Simulation of Surface Step Effects on First Dislocation Emission in Nanoindentation

To study the effects of surface step on the first dislocation emission in nanoindentation, a large-scale atomistic resolution simulation on thin aluminum film nanoindentation was investigated using quasicontinuum method. The results show that surface step has no effect on the strength of first dislocation emission in nanoindentation when there is no contact between the indenter and surface step. For the contact case, the strength of first dislocation emission may decrease by 23%-63% because of the stress concentration induced by surface step itself and by the decreased initial contact area between the indenter and surface step.