SIZE EFFECTS OF DISLOCATION PATTERNING IN FATIGUED METALS

The finite-size analog of the Walgraef-Aifantis (WA) model of the ''reaction + diffusion'' type has been proposed to explain the size effects of dislocation patterning in fatigued metals. It has been demonstrated that the formation of certain patterns can be understood as a result of competition between the intrinsic length scales of the WA-model and the linear size of the system which can be thought of as grain size, L. In our computer stimulations we demonstrate that depending on the value of grain size L, one can obtain formation of the ladder structure of persistent slip bands (L = 13 mu m), dislocation grids overlying grain boundaries (L = 1 mu m) or dislocation patterning can become prohibited when L --> 0.1 mu m and the system returns to the thermodynamic branch of solutions.