INVESTIGATION OF SOME SELECTED METALLURGICAL PROBLEMS WITH THE TOMOGRAPHIC ATOM-PROBE

The tomographic atom probe is a new instrument which enables a small v olume of a metallic material to be reconstructed in 3D on a near-atomi c scale. The basic principles on which the tomographic atom probe reli es are briefly described. The performance of this new generation of ap paratus is illustrated on the ground of some specific experiments. The intrinsic resolution of the spatial detector that was designed and de veloped is estimated. Several 3D atomic reconstructions of materials a re provided. Images related to the investigation of precipitation proc esses in two-phase nickel-base superalloys, grain-boundary segregation effects as well as G-phase formation related to the spinodal decompos ition of the ferrite in duplex stainless steels are given as illustrat ions. The quantitativity of composition measurements and the mass reso lution of the instrument are discussed.