A NEW DYNAMIC-MODEL FOR STUDY OF DISLOCATION PATTERN-FORMATION

Based on the principle given in nonlinear diffusion-reaction dynamics, a new dynamic model for dislocation patterning is proposed by introdu cing a relaxation time to the relation between dislocation density and dislocation flux. The so-called chemical potential like quantities, w hich appear in the model can be derived from variation principle for f ree energy functional of dislocated media, where the free energy densi ty function is expressed in terms of not only the dislocation density itself but also their spatial gradients. The Linear stability analysis on the governing equations of a simple dislocation density shows that there exists an intrinsic wave number leading to bifurcation of space structure of dislocation density. At the same time, the numerical res ults also demonstrate the coexistence and transition between different dislocation patterns.