A brief summary is firstly presented concerning up-to-date experimental studies of the formation of amorphous alloys (metallic glasses) in binary metal systems by ion beam mixing of nanosized metal–metal multilayers. Secondly, under the framework of Miedema's theory, thermodynamic modeling of crystal-to-amorphous transition is described with special consideration of the effect of the excess interfacial free energy on the alloy phase formation. Thirdly, in some representative systems, glass-forming ranges are calculated directly from their realistic interatomic potentials by determining the critical solid solubilities of the systems by molecular dynamics simulations. Finally, a comparison between irradiation and thermally induced amorphization in the metal–metal multilayers is also discussed.