Dislocation pair correlations from dislocation dynamics simulations.

The concept of stochastic fiber process is used in conjunction with the method of dislocation dynamics simulation to compute the pair correlations in three-dimensional dislocation systems. The results show that the pair correlations exhibit oscillatory behavior as a function of the radial distance and that the correlations are highly anisotropic in the crystal and dislocation line orientation spaces. The correlation oscillations are found to have smaller magnitude at higher strain levels and to decay as a function of distance to unity or to asymptotic values slightly below unity in some cases, which indicates that dislocations can be uncorrelated or anti-correlated at long range. The results suggest that incorporating the dislocation pair correlations in density-based kinetic dislocation models is not an easy task because of the need to represent the correlations as functions of three spatial coordinates and two line-orientation coordinates. [ABSTRACT FROM AUTHOR]