The focus of researchers studying severe plastic deformation on the final grain size of material is often preventing them from observing a much wider spectrum of alterations to material defect structure. It can be asserted that the decrease in material grain size is, in fact, only the consequence of many different processes accompanying plastic deformation in metals. We have performed a constitutive experimental, FEM and discrete complex based studies for two copper alloys subjected to ECAP and MDF deformation processes. This combination of methods allows for recognising complementary microstructural effects, such as micro- and macro-localization phenomena, coupled dislocation cells and grains evolution, inhomogeneities of triple junction network and ultrafine grain emergence. In many cases, the obtained deformational inhomogeneities play a substantial role both for deformation at macro- and microscale levels. Heterogeneity of grain boundary junction network could be critical for design of nanostructured copper-based alloys suitable for electrical applications.