Analysis of the influence of loading and the plasticity index on variations in surface roughness between two flat surfaces

Contact between two highly loaded flat surfaces is examined. In these experiments, a polished, hard metal surface was pressed against a rough aluminium alloy surface. The goal of the experiments was to flatten the peaks on the rough surface by plastic deformation. The experiments elucidated the relation between the normal load and the plasticity index, ψ, and the plastic deformation of the surface roughness peaks in the softer material. The results showed a significant reduction in surface roughness. Increasing the load caused a gradual reduction in the surface peaks. However, based on the values of the plasticity index ψ, it can be concluded that the peaks of the softer material underwent plastic deformation, regardless of the load.