This review describes the current state of research on the formation of a nanocrystalline structure in amorphous alloys under thermal and deformation effects. The processes of formation of nanocrystals in homogeneous and heterogeneous amorphous structures (nanoglass) are considered. Changes in the magnetic and mechanical properties during the formation of a composite amorphous-nanocrystalline structure with different structural parameters are analyzed. The possibility of amorphous phase rejuvenation from a partially crystalline structure under cryogenic thermocycling treatment is shown.