Mesoscopic simulations of plastic deformation

Abstract

This review is focused on recent progress achieved by mesoscopic simulations of plastic deformation. The methods presently available for discretizing the dislocation lines are critically discussed with emphasis on a new lattice-based model. Progress in large-scale simulations is represented by a study on the influence of long range elastic stresses on the formation of dislocation patterns in fcc crystals. A hybrid discrete-continuum method that provides an exact treatment of the boundary conditions is described and illustrated by an investigation of the critical conditions for dislocation motion in the channels of γ /γ superalloys.

The geometry of catastrophic fracture during high temperature processing of silicon

“…The stress-strain curves were calculated from dislocation dynamics simulations using the open source Micromegas code. This software is a development of the work of Devincre et al (2001). Dislocations are allowed to glide on all the 12 slip systems of {111} planes along 110 directions.…”

Simulation of dislocation patterns in multislip

“…The dislocations are uniformly distributed in space and no trace of emerging structure is found. In the case where only shortrange interactions are accounted for, a central dislocation-poor region is formed [7]. Its radius is larger than the cut-off radius, so that this structure is not an artifact due to the truncation of the elastic interactions (in contrast to a common belief, such artifacts arise only on microstructures that are let to relax in the absence of applied stress).…”

“…This makes it possible to treat dense configurations in material volumes with dimensions larger than those of a typical dislocation cell. The basic principles of these three-dimensional (3-D) simulations can be found in several references [6][7][8][9] and will not be detailed here.…”

“…Numerical experiments were designed in order to check the influence of close and distant interactions between dislocations on the evolution of the microstructure and on the flow stress [7]. A cutoff radius was introduced of the order of q À1=2 (about 1 lm).…”

A new fast finite element method for dislocations based on interior discontinuities

“…In these models, the image stresses are generally computed approximately from empirical/analytical formulae, which are generally valid only for simple boundary geometries. According to Devincre et al [9], one of the greatest difficulties in such models is that the boundary condition are not met exactly.…”