The requirement of thermal stability of nanocrystalline materials can be fulfilled with a composite approach. However, utilizing a two-phase approach includes additional constraints concerning the synthesis and processing, especially of massive nanostructured materials. Here, the potential of deformation processing for synthesizing nanoscale composite structures with uniform microstructures in bulk shape is analyzed for a series of Cu-rich alloys. The results are discussed with respect of governing materials properties that determine the feasibility of a composite approach in combination with severe plastic deformation to obtain massive nano-composite materials with high thermal stability.