The simulation of the parallel dynamics of edge dislocations in a 2-dimensional hexagonal lattice was carried out on a large scale by means of coarse graining in the absence of external strain. In order to study the effect of climb upon dislocation pattern formation, (i) isotropic (ii) biased (iii) only glide mobility was allowed. Dislocations with opposite Burgers vectors, close to each other, were annihilated. The main result was that, in cases (i) and (ii), a cellular structure emerged. In case (ii), this happened after a longer transient, whereas (iii) gave a diffuse pattern as in previous single slip plane simulations. In the course of the evolution of dislocation number and cell size they statistically satisfied Holt’s relationship. The cell structure appeared to have a characteristic cell-size; in contrast to fractal examples in the presence of mechanical strain. In spite of the simplicity of the model, the results were consistent with recently detected low-density dislocation patterns in melt-grown non post-deformed crystals.

Dislocation Patterning - the Role of Climb in Meso-Scale Simulations. B.Bakó, I.Groma, G.Györgyi, G.Zimányi: Computational Materials Science, 2006, 38[1], 22-8