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Nanoscale Metal-Metal Contact Physics From Molecular Dynamics: The Strongest Contact Size, Hojin Kim, Alejandro Strachan

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Using molecular dynamics we find that the tensile strength of the contacts between two clean platinum surfaces with nanoscale asperities is strongly size dependent with a maximum strength for contact lengths of approximately 5 nm. This is the first time a strongest size is observed in single crystals. The strengthening with decreasing size down to 5 nm results from a decrease in the initial density of mobile dislocations available for plastic deformation and the subsequent weakening originates from a reduction in the constraint to mechanical deformation inside the contact by the bulk.