Published online by Cambridge University Press: 21 March 2011
Atom probe tomography provides one of the most effective tools to characterize the solute distribution and precipitation that occurs in pressure vessel steels and associated model alloys during irradiation. The three-dimensional atom probe is able to experimentally determine the elemental identities of the atoms and their spatial coordinates with near atomic resolution so that their distribution within small volumes of the specimen can be reconstructed and analyzed. This technique together with conventional atom probe field ion microscopy has been applied to many different types of pressure vessel steels and model alloys and has revealed and characterized several different nanostructural transformations. These radiation induced or enhanced processes lead to the formation of copper-nickel-manganese-silicon-enriched precipitates, and solute segregation to dislocations, dislocation loops, nanovoids and boundaries.