Mechanism of Abrasive Wear in Nanomachining

In this study, nanomachining is utilized to investigate the abrasive wear mechanism that produces a nano scale groove on a bulk material. Two different tools (Berkovich and Conical) with the same tip radius (100 nm) but different edge geometries were used for machining both Cu- and Ni-coated materials with a nanoindenter that was equipped with a nano scratching attachment. It was found that the generated forces (normal and cutting) increased with the increase of depth of cut; however, the generated normal force at the minimum depth of cut (50 nm) was more than the critical force for all machining conditions. Therefore, at the minimum depth of cut, groove formation started with the ploughing mode of abrasive wear mechanism, then the cutting mechanism activated along with the ploughing mechanism above a 100 nm depth of cut. The percentage values of these two mechanisms were determined and utilized to determine the dominant mode of the abrasive wear mechanism for producing a nano scale groove on a metal surface and, to correlate this, abrasive wear mechanism with the co-efficient of friction (μ) at different machining conditions. The results also showed that the co-efficient of friction (μ) increased when ploughing was the dominant mode of abrasive wear mechanism to produce a nano scale groove. Thus, μ was found to be proportional to the ploughing mode of abrasive wear mechanism in nanomachining.