Amorphous phase formation in irradiated intermetallic compounds

A variety of intermetallic compounds have been irradiated with high energy ions to determine the criteria for an amorphous transformation. Those compounds with limited compositional range or solubility tend to become amorphous during irradiation, whereas those compounds with wide solubility tend to remain crystalline. This solubility criterion is consistent with the concept that a critical defect density which will result in a greater free energy of the crystal phase than the free energy of the amorphous phase is necessary for the amorphous transformation. This critical defect density is lower in those compounds that become amorphous. The ionicity criterion of Naguib and Kelly does not work for these intermetallic compounds, but the temperature criterion is probably valid and is, in fact, directly related to the proposed solubility criterion.