ON THE PHASE FORMATION DURING ION-BEAM MIXING

The phase formation during ion-beam mixing of binary transition-metal alloys have been studied by use of 500-keV Xe+ in the temperature range from liquid-nitrogen temperature to 600 K. Especially the composition ranges, where single-phase amorphous structures occur, i.e., the glass-forming ranges, have been investigated. It is proposed that, based on semiempirical data on free energies and using the common-tangent construction, glass-forming ranges may be estimated for the case of alloys with negative heat of mixing. In the case of positive heat of mixing, the initial thin-film structure is near thermodynamic equilibrium. However, for small values of the heat of mixing, it is still possible to form amorphous structures. In the absence of chemical driving forces, this formation cannot be explained in a similar way as for the case of negative heat of mixing. © 1990.