Atomistic simulations of elastic deformation and dislocation nucleation during nanoindentation

• Published in: Journal of the mechanics and physics of solids 2003-05, Vol.51 (5), p.901-920
• Main Authors: Lilleodden, E.T., Zimmerman, J.A., Foiles, S.M., Nix, W.D.
• Format: Article
• Language: English
• Subjects: Atomistic; Computational techniques; Condensed matter: structure, mechanical and thermal properties; Contact mechanics; Defects and impurities in crystals; microstructure; Dislocations; Elasticity, elastic constants; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Grain boundaries; Indentation and hardness; Mathematical methods in physics; Mechanical and acoustical properties of condensed matter; Mechanical contact (friction...); Mechanical properties of solids; Physics; Solid mechanics; Structural and continuum mechanics; Structure of solids and liquids; crystallography; Theories and models of crystal defects; Tribology and mechanical contacts
• ISSN: 0022-5096
• DOI: 10.1016/S0022-5096(02)00119-9

Nanoindentation experiments have shown that microstructural inhomogeneities across the surface of gold thin films lead to position-dependent nanoindentation behavior [Phys. Rev. B (2002), to be submitted]. The rationale for such behavior was based on the availability of dislocation sources at the grain boundary for initiating plasticity. In order to verify or refute this theory, a computational approach has been pursued. Here, a simulation study of the initial stages of indentation using the embedded atom method (EAM) is presented. First, the principles of the EAM are given, and a comparison is made between atomistic simulations and continuum models for elastic deformation. Then, the mechanism of dislocation nucleation in single crystalline gold is analyzed, and the effects of elastic anisotropy are considered. Finally, a systematic study of the indentation response in the proximity of a high angle, high sigma (low symmetry) grain boundary is presented; indentation behavior is simulated for varying indenter positions relative to the boundary. The results indicate that high angle grain boundaries are a ready source of dislocations in indentation-induced deformation.