It was recalled that, in austenitic stainless steels, the separation of Shockley partial dislocations was known to play an important role in plastic deformation and to produce various deformation microstructures. Theoretical calculations were carried out in an attempt to explain the origin of the deformation microstructures, which included large stacking faults and twins. Force-balance equations for the leading and trailing partials were established by considering the Peach-Koehler force from an applied stress field, repulsive forces between leading and trailing partial dislocations, attractive forces due to the stacking-fault energy and a resistance (or damping) force opposing the glide of the partial dislocations. An expression for the separation distance was derived, for a simple dislocation and stress arrangement, from the force balance equations. The results indicated that the separation distance varied with the directional relationship between the applied stress and the Burgers vectors of glide dislocations. Also, the separation distance increased with the applied stress and could diverge when the applied stress exceeded a critical stress. The critical stress could be readily achieved in the uniform strain range by strengthening means such as irradiation, lowered test temperature and increasing strain or strain-rate. By using a stress-based analysis, some predictions were made of the effect of radiation-induced defects upon deformation microstructures in austenitic stainless steels.

On the Stress Dependence of Partial Dislocation Separation and Deformation Microstructure in Austenitic Stainless Steels. T.S.Byun: Acta Materialia, 2003, 51[11], 3063-71