The mechanism which governed the conservative climb of dipoles, and a new dislocation dynamic model for single slip, were proposed. According to this model, the formation of a planar array in stage-I of crystal hardening was predicted; in agreement with experimental results. This model took account not only of the drift and climb mechanism of dipoles, but also of the 3-dimensional movement of mobile dislocations of both signs, via slip and cross-slip. The multiplication and reaction of dislocations were also considered in a different manner to that in previous studies. Linear stability and non-linear bifurcation analyses showed that dislocation patterns corresponded to the stable structure which formed as a result of the dynamic instability of a statistically homogeneous dislocation distribution which was driven far from equilibrium. The critical conditions corresponded to Hopf bifurcations and Turing instabilities. The analytical form of the dislocation pattern near to a singular point was derived. By applying Orowan's formula, the correlation between the planar array and the easy slip behavior in stage-I of hardening was clarified. It was shown that, although the total dislocation densities remained unchanged just after dislocation patterns appeared, hardening began to decrease. This demonstrated that the influence of dislocation patterns upon hardening was more fundamental than that of the dislocation density itself.

Dynamic Analysis of the Formation of Dislocation Patterns in the Easy-Slip Stage of Single Crystals. H.Huang, Z.Duan, W.Wang: Acta Mechanica Sinica, 1998, 30[1], 65-75