Nanoscopic surface texture formed by indentation and sliding of a smooth wedge tool

To achieve reliable replication of a flat tool surface through a metalforming process with nanometer-scale surface roughness, a wedge tool was indented and slid under a constant normal load. In a workpiece finished with abrasive paper, some of the initial valleys remain on the tested surface, though at the boundary contact area the surface roughness is as small as that of the tool. The final surface roughness of the workpiece was much reduced by starting with a smoother surface of the workpiece and by unlubricated short sliding. A nanoscopically smooth surface of 0.8 nm sRa was obtained with a gold-coated copper workpiece after unlubricated indentation and sliding. This suggests the beneficial effect of a soft surface film coated over a hard substrate, causing complete filling of the interfacial vacancies.