Atomistic description of coupled thermal-mechanical stresses on a gold/HOPG nanocontact

Atomistic simulation is used to study the nanoscale contact between gold and graphite at a range of normal loads and temperatures. Simulations show that the size of the contact is affected by both temperature and load. It is found that the simulation contact areas are larger than those predicted by a continuum adhesive contact mechanics model and that the difference between the atomistic and continuum descriptions of the contact is greater at higher temperatures. This origin of this difference is explored in terms of the effects of temperature on the elastic-plastic transition, the adhesive strength of the interface and the elasticity of the materials. A temperature-corrected adhesive contact model is proposed, which partially captures the behavior observed in the simulations. Analyses of the stress within the materials suggest that coupling of temperature and load may also occur, which results in a contact area that differs from that predicted from the summation of independent load and temperature effects. (C) 2017 Elsevier B.V. All rights reserved.