STATIC JUNCTION GROWTH DURING FRICTIONAL SLIDING OF METALS

We report a molecular dynamics simulation of junction growth during frictional sliding of a nanometre scale copper tip on a copper substrate under compressive loading. Much less junction growth is seen under tensile loading. In contrast to the usual form of junction growth discussed by Tabor [Proc. R. Soc. A 251, 378 (1959)] the junction growth we see does not lead to an increase in the frictional force. Under both compressive and tensile loading we see material transfer from the tip to the substrate.