Evolution of dislocation structure in low-stability states during deformation of solid solutions of alloys

Abstract

The results of a study of the evolution of the dislocation structure of polycrystals of homogeneous solid solutions in low-stability states in Cu-Mn-based alloys with a FCC crystal lattice are presented. It is found that each stage is characterized by its own deformation carrier in the form of a certain dislocation substructure (DSS), the volume fraction of which has a maximum at this stage. At the same time, at the considered stage, the carrier of deformation of the previous stage gradually disappears as the degree of deformation (ε) increases, however, a carrier of deformation of the subsequent stage appears. In a certain range of values of ε, deformation carriers characteristic of the previous, considered and subsequent stages simultaneously coexist. It is shown that transitions from some types of DSS to other types occur in some intervals of values of the degree of deformation ε. It is discovered that each stage of deformation has its own DSS - carriers of deformation. The transition from stage to stage is accompanied by the formation of new deformation carriers, which is a characteristic feature of weakly stable states of the system. Naturally, the described picture is observed because the study is carried out at such a grain size, which suggests the possibility of implementing a low-stability structural-phase state of the alloy, since the grain size acts in this case as a kind of control parameter.