Application of ion-beam-analysis techniques to the study of irradiation damage in zirconium alloys

Ion-beam-analysis techniques are being used to provide an understanding of the nature of collision cascades, irradiation-induced phase changes, lattice location of solute atoms and defect-solute atom interactions in various zirconium alloys. In zirconium intermetallic compounds, such as Zr3Fe, Zr2Fe, ZrFe2, and Zr-3(Fe-x,Ni-1-x), electron and ion irradiations have been used to obtain detailed information on the crystalline-Eo-amorphous transformation occurring during the irradiation. Transmission-electron-microscopy (TEM) observations have provided information on the nature of the damage produced in individual cascades, the critical dose required for amorphization, and the critical temperature for amorphization. In a study on the electron-energy dependence of amorphization in Zr3Fe, Zr2Fe and ZrCr2 in situ high-voltage-electron-microscope investigations were combined with high-energy forward-elastic-recoil measurements to yield information on the threshold displacement energies for Zr and Fe or Cr in these lattices, as well as the role of secondary displacements of lattice atoms by recoil impurities (C,O) at low electron energies. In Zr implanted with Fe-56 ions and subsequently bombarded with Ar-40 ions at 723 K, subsequent secondary-ion-mass-spectrometry (SIMS) analyses were used to monitor che effect of irradiation on the migration of Fe in the Zr lattice. In addition, ion-channeling investigations have been used to determine the lattice sites of solute atoms in Zr as well as the details of the interaction between the solute atoms and the irradiation-produced defects.