Bridging steady-state deformation behavior at low and high temperature by considering dislocation dipole annihilation

For single phase metals, both the stress exponent n and activation energy Q of stationary deformation significantly change from low to high deformation temperature. This paper illustrates a recently developed model of dislocation density evolution, which is able, to explain that transition. Important model components in this respect are the consideration of dislocation dipoles (represented as distribution of dipole heights) as well as of dislocation annihilation mechanisms of different kinetics: glide-induced dislocation-dislocation reactions and climb of edge dipole constituents. The model exhibits a transition with decreasing temperature from dislocation climb to glide as the decisive annihilation kinetics, which in turn is reflected in the steady-state deformation behavior. (c) 2005 Elsevier B.V. All rights reserved.