Dislocation distribution under a microindentation into an iron-silicon single crystal

Abstract

A transmission electron microscopy study of the dislocation distribution under an indentation has revealed first that a complex sequence of loop nucleation, cross-slip and renucleation results in a cross-like network at the free surface and a square-like network underneath. These dislocation distributions are made up of two types of dislocation: redundant dislocations responsible for general plasticity and work hardening, and shielding dislocations responsible for the equilibrium of forces. The former are roughly an order of magnitude more prevalent. The total number of dislocations are consistent with continuum plasticity theory while the shielding density is consistent with a proposed superdislocation pile-up model.