EVOLUTION OF MICROSTRUCTURE IN NICKEL BY LOW-ENERGY DEUTERIUM ION IRRADIATION

To understand the characteristics of damage in Ni by low-energy deuterium-ion irradiation, TEM observation and SIMS analysis have been carried out. Because of strong binding between an interstitial and a deuterium atom, nucleation of interstitial loops by deuterium-ion irradiation (0.5 to 5.0 keV) is enhanced. The density and the size of the loops increase with irradiation and the dislocation density exceeds 10(16)/m2 in the region where deuterium ions are injected. In the irradiation at room temperature, immobile vacancies, which act as good traps for deuterium atoms, are accumulated. At 300-degrees-C, however, dislocation loops and cavities are formed. Irradiation with 0.5 keV ions produces little displacement damage but platelet-like deuterium clusters are formed due to the localization of the injected deuterium atoms.