Atomic-Scale Issues in Tribology: Interfacial Junctions and Nano-elastohydrodynamics

Abstract

Advances in computer-based modeling and simulation methodologies and capabilities, coupled with the emergence and development of high-resolution experimental techniques, allow investigations of tribological phenomena with unprecedented atomic-scale spatial and temporal resolution. We focus here on molecular dynamics simulations of formation and properties of interfacial junctions and on nano-elastohydrodynamics in sheared lubricated junctions. Simulations predict that upon approach of a metal tip to a surface a jump-to-contact instability occurs and that subsequent nanoindetation leads to plastic deformation of the gold surface. Retraction of the tip from the surface results in formation of a connective junction, or wire, of nanoscale dimensions, whose elongation mechanism consists of a series of plastic stress-accumulation and stress-relief stages which are accompanied by structural order−disorder transformations. These transformations involve multiple-glide processes. The yield-stress of a gold nanowire...