Fractal contact behavior of single crystal copper substrate and rigid plane

Abstract

The micro-nanoscopic morphology of the contact surfaces directly affects the tribological behavior between the contact surfaces. In this paper, a single crystal copper substrate with nano rough surfaces is characterized based on the fractal theory, and the nano rough contact model which could exist stably at room temperature (298 K) is established. The contact behavior between rigid plane and elasto-plastic rough substrate is analyzed. It is found that only a few higher asperities enter the contact area at the initial contact stage, causing large fluctuations in contact force. However, due to the small interaction between the asperities, the contact area is approximately linear with the contact force. If the ratio of real contact area to nominal contact area is greater than 17%, the contact force and contact area both increase with the increase of indentation depth, but the contact area-contact force curve deviates from the linear relationship gradually due to the intensification of material deformation and the interaction between asperities.