Nanoindentation as a Probe of Nanoscale Residual Stresses: Atomistic Simulation Results

Abstract

Results from two sets of molecular dynamics simulations are reported. In the first set of simulations a nanoscale tip was used to indent single-crystal gold lattices subjected to external strains. These were carried out to explore possible relationships between nanoindentation curves and elastic properties of uniformly strained films. The changes in the slope of the loading curves reflect the stress state of the sample. In the second set of simulations the use of shallow nanoindentation for mapping nonuniform residual surface stress near a dislocation intersecting a surface was tested. Correlation between the maximum force on the tip and the initial local stresses at the point of indentation were observed. Preliminary atomistic simulations indicate that atomic-force microscopy can be used as a nondestructive, nanoscale probe of the surface stress distributions.