Dislocation nucleation and defect structure during surface indentation

TLDR

The study atomistically images dislocation nucleation during displacement‑controlled indentation on a passivated metal surface. The authors model indentation by coupling an atomistic metal with a hard‑sphere indenter, locate dislocations via centrosymmetry deviations, and compare the results to empirical nucleation criteria and continuum elasticity predictions. On Au(111), partial dislocation loops nucleate beneath the surface within the indenter contact area.

Abstract

We model indentation of a metal surface by combining an atomistic metal with a hard-sphere indenter. This work provides atomistic imaging of dislocation nucleation during displacement controlled indentation on a passivated surface. Dislocations and defects are located and imaged by local deviations from centrosymmetry. For a Au(111) surface, nucleation of partial dislocation loops occurs below the surface inside the indenter contact area. We compare and contrast these observations with empirical criteria for dislocation nucleation and corresponding continuum elasticity solutions.