Simulations of the 3-dimensional elastic stress fields of finite dislocation walls with spatial disorder were performed. Each wall consisted of 40 dislocations with an average spacing of 40nm. The dislocation lines were decomposed into piecewise-straight segments which represented the translational vectors of a face-centered cubic lattice. Spatial disorder of the walls was produced by incorporating curved dislocations The results confirmed that disorder, of the dislocation lines which were involved, altered the stress fields that were associated with the walls. In the immediate vicinity of the walls (that is, within 2 times the dislocation separation) the shear stress was only weakly dependent upon the degree of order, and decayed as predicted for an infinite low-angle tilt boundary. Further away from the walls (between 2 and 60 times the dislocation separation), a maximum shear stress occurred, which decreased with increasing degree of disorder. The long-range stress fields (at a distance of more than 60 times the dislocation separation) were only weakly affected by the type of disorder that was imposed. The fact that the shear stress profile exhibited a maximum in the intermediate range was attributed to the use of finite rather than infinite walls. A decrease in the maximum shear stress with decreasing order, in the intermediate range, was explained in terms of self-screening effects.

D.Raabe: Computational Materials Science, 1995, 4[2], 143-50