EVOLUTION OF DISLOCATION STRUCTURE OF POLYCRYSTALS OF HOMOGENEOUS COPPER-MANGANESE SOLID SOLUTIONS UNDER CONDITIONS OF PLASTIC DEFORMATION

The results of an electron microscopy study of the dislocation structure evolution in polycrystals of Cu-Mn homogeneous solid solutions having an fcc-lattice are presented. A scheme of the dislocation substructure rearrangements identified on the stress-strain curves in the transitions from one stage to another is constructed for the Cu-Mn alloys as a function of the concentration. A critical role of solid solution strengthening in the development of dislocation substructures (DSS) in the Cu-Mn alloys with an fcc crystal lattice is identified, which are the principal deformation carriers for a particular deformation stage. It is shown that the transitions from one DSS type to another occur in specific strain degree intervals [epsilon]. It is revealed that every deformation stage has its corresponding DSSs--deformation carriers. A stage-to-stage transition is followed by the formation of new deformation carriers, which is a characteristic feature of the low-stability states of this system. Keywords: Cu-Mn alloys, solid solution strengthening, dislocation substructures, low-stability states.