Concurrent atomistic-continuum simulations of uniaxial compression of gold nano/submicropillars

http://dx.doi.org/10.1080/09500839.2018.1515506

Abstract

In this work, uniaxial compression of nano/submicropillars in Au with the initial diameter D between 26.05 and 158.53 nm was modelled by concurrent atomistic-continuum simulations. Two models with distinct surface facets were employed to explore the surface facets-dependent extrinsic size effects on the plastic deformation of pillars. It is found that (i) the yielding in pillars with smooth surfaces was controlled by dislocation nucleation from the two ends of the pillars, and (ii) in pillars with faceted surfaces, dislocations were initiated from the sharp edges on the surface. As a result of the differences in the plastic deformation mechanism between the two models, the yield stress decreased exponentially and increased nearly linearly with respect to an increasing D in pillars with smooth and faceted surfaces, respectively.