Adhesive wear mechanisms in the presence of weak interfaces

Despite the relevance of wear in many engineering applications, our understanding of the connection between mechanisms at the nanoscale and the observed wear rates of contacting parts at the macroscale remains limited. Recent work in our group has therefore focused on physics-based models of adhesive wear mechanisms, identifying a material-dependent critical length scale for wear particle formation. Upscaling of these findings, though, still remains challenging. One problem is that only strong adhesive bonds between contacting solids were considered. In the present contribution, we therefore extent this framework to include weaker interfaces, which are expected at typical contacts due to lattice mismatch, surface passivation, or lubrication. We use atomistic simulations on an amorphous model material to propose a mechanism map based on material properties and local contact geometry for wear particle formation and surface damage at the single-asperity scale. Our results imply that the local slopes of rough surfaces govern a transition from asperity collisions with plastic damage and wear particle formation at high roughness to slip without significant damage for flatter surfaces, comparable to a run-in process.