Concurrent Annealing Of Vacancy-Type And Interstitial-Type Damage In Neutron Irradiated Stainless Steel

ABSTRACTAnalysis of the effect of annealing on change in void and loop size distributions provided insights that complement microstructural characterization using transmission electron microscopy (TEM). The predictions of concurrent vacancy-type and interstitial-type damage annealing are applied to measurements in neutron-irradiated austenitic stainless steels. Irradiation at 330°C produces void and loop microstructures for which the measured annealing response is in accord with predictions. Irradiation at 275° produces only Frank loop microstructure for which the annealing response cannot be predicted from measured microstructures. The model predictions are based on an assumed vacancy source not detected using TEM. The measured loop microstructure is typically reported to be interstitial in character but this analysis suggests that a significant component of the loop population is vacancy-type damage based on defect inventory and kinetic arguments.

High Resolution Transmission Electron Microscopy of Defect Clusters in Aluminum During Electron and Ion Irradiation at Room Temperature

Defect clusters in Al during electron and ion irradiation have been investigated using highresolution transmission electron microscopy (HRTEM). An ION/HVEM system which consists of a high-voltage TEM and ion implanters was used for in-situ observation of damage evolution under 1000 keV electrons and 15 keV He+ irradiation at room temperature. HRTEM of Al in [110] orientation showed many planar defects along { 111 } planes during electron irradiation, while a high density of small polyhedron-shaped cavities (He-bubbles) was observed in addition to the planar defects after He+ irradiation. Multi-slice image simulation of various models of dislocation loops indicated the planar defect as an interstitial-type Frank loop.