Effect of Surface Energy on Shearing of Metal Asperities Contact at the Nanoscale

DY Yu and J Wang and M Ma and YG Meng, JOURNAL OF PHYSICAL CHEMISTRY C, 124, 27436-27441 (2020).

DOI: 10.1021/acs.jpcc.0c06371

In the long history of study on friction and wear phenomena, the single asperity system (SAS) is found to be the primary unit to understanding the macroscopic mechanisms. Despite of the importance, existing experimental and simulation techniques are difficult to give a unified understanding on this complex multi-scale phenomenon. Here, we study the shearing of the SAS by using full atomic molecular dynamics simulations. The result agrees quantitatively with the existing experimental measurements. Then, a detailed analysis from the energy perspective is performed to reveal the underlying physical mechanism of the SAS friction process. Results show that surface energy gamma of the SAS plays an important role on its tribology behavior at the nanoscale. Our results point out the deficiency of the adhesion friction theory at the nanoscale, providing insights in the origin of friction and wear and benefit its implications on macroscopic tribological problems.

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