INTERPRETATION OF PLASTIC-DEFORMATION BY MEANS OF DISLOCATION-DISCLINATION REACTION-KINETICS

The microstructure development under plastic deformation up to large s trains is modelled by means of four-component reaction kinetics for th e densities of mobile and immobile dislocations and disclinations. The resulting system of nonlinear differential equations is able to descr ibe the transition from a dislocation-dominated to a disclination-cont rolled kinetics running into a (quasi-)stationary state, and finally, into an instability. For an estimation of the resulting flow stress th ree contributions are taken into account: a redundant dislocation cont ribution governed by a Taylor law, a subgrain size contribution govern ed by a Hall-Fetch relationship, and a misorientation contribution. To connect the density of sessile disclinations to the mean subgrain siz e and the mean misorientation, new relationships based on stochastic g eometry are used. (C) 1997 Elsevier Science S.A.