The role of surface shear strains in the adhesion of metals. Part I

Abstract

The effect of surface shear strains on the adhesion of copper, aluminum, and gold surfaces is examined. In particular, the effect of shear strains on the structure of metal surfaces and substrata subsequent to adhesion is elucidated. It is shown that shear strains are necessary for adhesion to occur under most circumstances when unlubricated metals are in contact. Shear strains are very effective in removing surface oxides, and these oxides are buried at below the common interface. Shear strains roughen the surface, increase the amount of atomic contact, and produce a work-hardened zone near the common interface, all of which tend to make the adhesion more effective. In general, the concept of friction and adhesion advocated by the Cambridge school is confirmed.