The Role Of Vorticity In The Formation Of Tribomaterial During Sliding

Abstract

The formation of tribomaterial during sliding is well documented for a wide range of materials. Transfer, adhesion, mechanical mixing and formation of nanocrystals are commonly reported, but the mechanisms involved have not been well understood. Recently, molecular dynamics (MD) simulations have been performed to obtain new information on the response of materials to sliding interactions. The results help to explain experimental observations on simple metals such as copper, bulk metallic glasses and multi-component nanocomposite coatings. When the sliding speed is sufficiently high, the strain rate allows vorticity to develop. It is suggested that the resulting eddies are largely responsible for frictional energy dissipation and mechanical mixing in both crystalline and amorphous materials and for the shear mixing of soft embedded particles in nanocomposite coatings. Similarities of flow behavior with that of fluids are noted.