Influence of stacking faults and alloy composition on irradiation induced amorphization of ZrCr{sub 2}, ZrFe{sub 2} and Zr{sub 3}(Fe{sub 1-x},Ni{sub x})

These Zr-based intermetallics were irradiated with high-energy electrons at the ANL HVEM/Tandem facility. Although ZrCr{sub 2} and ZrFe{sub 2} have the same Laves phase C15 fcc crystal structure, their critical temperatures for amorphization under electron irradiation were 180 and 80 K, showing that Cr substitution for Fe in the sublattice had a marked effect on annealing. The low temperature dose to amorphization was higher in ZrFe{sub 2} than in ZrCr{sub 2} by a factor of two. Presence of a high density of stacking faults had a strong effect on amorphization in both compounds causing the critical temperature to be increased by 10-15 K. By contrast, addition of Ni to Zr{sub 3}(Fe{sub 1-x},Ni{sub x}) had no effect on amorphization behavior for x=0.1 and 0.5. These results are discussed in terms of current models of amorphization based on defect accumulation and attainment of a critical damage level, such as given by the Lindemann criterion