Calculation of stress-strain curves by using 2 dimensional dislocation dynamics

A method is presented to derive stress-strain curves by using 2 dimensional dislocation dynamics. The simulation treats plastic deformation of single, grains, in which one or more slip systems are active. The involved dislocations are regarded as infinite straight line defects which are embedded in an otherwise isotropic linear elastic medium. As the model is two dimensional only edge dislocations are incorporated, The calculation of the local stressfield considers the long range elastic stress contribution of ail dislocations within the grain, of the externally imposed stressfields and of the short range stressfield imposed by large angle grain boundaries. Due to the net local value of the stressfield the dislocations may either glide or climb, Dislocation multiplication, annihilation and reactions are taken into account. Thermal activation is considered, The simulations allow to compute the evolution of the dislocation distribution, the stressfield and the plastic strain during a simulated deformation experiment. The latter quantities are used for the calculation of stress-strain curves.