Size effects of dislocation patterning in fatigued metals

Abstract 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 μ m), dislocation grids overlying grain boundaries ( L = 1 μ m) or dislocation patterning can become prohibited when L → 0.1 μ m and the system returns to the thermodynamic branch of solutions.

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