Surface plastic flow in polishing of rough surfaces

TL;DR

This study uses electron microscopy to observe how surface plastic flow occurs during polishing, revealing viscous-like material flow and layer bridging that lead to surface smoothening, offering new insights into polishing mechanisms.

Contribution

It provides novel microscopic evidence of viscous-like surface flow and layer bridging in polishing, advancing understanding of the process.

Findings

Asperity-abrasive contacts exhibit viscous behavior.

Surface smoothening occurs via layer bridging among asperities.

Insights are relevant for tribology and materials processing.

Abstract

We report electron microscopy observations of the surface plastic flow in polishing of rough metal surfaces with a controlled spherical asperity structure. We show that asperity--abrasive sliding contacts exhibit viscous behavior, where the material flows in the form of thin fluid-like layers. Subsequent bridging of these layers among neighboring asperities result in progressive surface smoothening. Our study provides new phenomenological insights into the long-debated mechanism of polishing. The observations are of broad relevance in tribology and materials processing.