Nanoindentation Simulation of a Thin Ni Film Using Hyper-QC
Ellad Tadmor (University of Minnesota), Woo Kyun Kim (University of Minnesota)
From Atomistics to Reality: Spanning Scales in Simulations and Experiments Symposium A
Mon 9:00 - 10:30
CIT 165
Recently in order to simultaneously span multiple length and time scales in atomistic simulations, we developed "hyper-QC", which is a method that combines finite temperature quasicontinuum (QC) and hyperdynamics within a single framework. This method accelerates times in a QC simulation while preserving the characteristic dynamics of the system. In this study we report the application of hyper-QC to the nanoindentation of a thin nickel film. To date atomistic nanoindentation simulations have failed to give correct predictions for some key properties, such as hardness, because the indentation rates in the simulations are orders of magnitude larger than those in experiments. Using hyper-QC and a novel bias potential based on the slip mechanism in fcc crystals, we are able to reduce the simulated indentation rate to approach experiments. The hyper-QC simulations reveal a number of rate-dependent mechanisms that affect the mechanical properties of the system, which are seen to approach the experimental values as the rate decreases.