Identification of the nature of neutron-irradiation-induced small point defect clusters in nickel by means of electron irradiation and defect structure development from collision cascade
Electron irradiation induced amorphization of FeTi and CoTi was studied by high voltage electron microscopy (HVEM) from 10 to 160°K. The complete amorphization was observed in both compounds, with the critical dose at 10°K and the critical temperature being about 1.7 dpa and 110°K for FeTi, and about 1.3 dpa and 90°K for CoTi. The onset of amorphization occurred in both compounds after substantial chemical disordering when irradiated below Tc, while the point defect clusters formed above Tc. In addition, the pseudo ten fold symmetry (PTEFS) diffraction spots were observed in selected area diffraction (SAD) pattern of both compounds prior to complete chemical disordering and thus complete amorphization.
AbstractFocused ion beam (FIB) induced damage in nanocrystalline Al thin films has been characterized using advanced transmission electron microscopy techniques. Electron tomography was used to analyze the three-dimensional distribution of point defect clusters induced by FIB milling, as well as their interaction with preexisting dislocations generated by internal stresses in the Al films. The atomic structure of interstitial Frank loops induced by irradiation, as well as the core structure of Frank dislocations, has been resolved with aberration-corrected high-resolution annular dark-field scanning TEM. The combination of both techniques constitutes a powerful tool for the study of the intrinsic structural properties of point defect clusters as well as the interaction of these defects with preexisting or deformation dislocations in irradiated bulk or nanostructured materials.
On the application of the weak-beam technique to the determination of the sizes of small point-defect clusters in ion-irradiated copper