PHASE FORMATION DURING ION-BEAM MIXING OF TRANSITION-METAL MULTILAYERS

Evaporated films of alternating layers of early and late transition metals have been ion beam mixed with inert-gas ions for the study of the phase formation during ion irradiation. The mixing was performed with 500 keV Ar+ and Xe+. In addition, a few co-deposited amorphous films were irradiated, using 200 keV Ne+ and 500 keV Xe+ ions. All the ions fully penetrate the films of approximate thickness 800 angstrom. The microstructure was investigated by transmission electron microscopy and X-ray diffraction. The homogeneity and composition were checked by Rutherford backscattering spectrometry. The glass-forming ranges of Fe-Zr, Co-Zr, Ni-Zr, Ni-Ti and Ni-Nb were studied as functions of composition, temperature (30-750K) and ion mass. The measured glass-forming ranges are discussed in relation to thermodynamic parameters such as the heat of mixing and equilibrium solid solubilities.