Nanoindentation as a probe of nanoscale residual stresses: Atomistic simulation results

Results from two sets of molecular dynamics simulations are reported. In th e first set of simulations a nanoscale tip was used to indent single-crysta l gold lattices subjected to external strains. These were carried out to ex plore possible relationships between nanoindentation curves and elastic pro perties of uniformly strained films. The changes in the slope of the loadin g curves reflect the stress state of the sample. Tn the second set of simul ations the use of shallow nanoindentation for mapping nonuniform residual s urface stress near a dislocation intersecting a surface was tested. Correla tion 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, nano scale probe of the surface stress distributions.