Molecular Dynamic Simulations of the Stick--Slip Phenomenon on the Surface of Cu Single CrystaL
单晶Cu表面黏-滑效应的分子动力学模拟

The mechanisms of micro stick-slip phenomenon were investigated with the 3D molecular dynamics simulation (MDS) of single-asperity dry friction on the surface of Cu single crystal. At the atomic scale, the regular arrangement of atoms on the sliding surface induced a large and a small " sawtooth " in the friction force curve, which can be explained by the appearance and disappearance of the dislocations on the sliding surfaces. The magnitudes of " sawtooth " depend on the load, sliding speed and the lattice difference across the sliding surface. The higher the load, the more atoms to be moved during dry friction, and the less the magnitude of the small " sawtooth ". The magnitude of the small " sawtooth " is linear to the sliding speed. The stick-slip phenomenon varies with sliding surfaces and different sliding directions, but the period of the " sawtooth " is just the lattice constant of the substrate along the sliding direction.