A 3D study of G-phase precipitation in spinodally decomposed α-ferrite by tomographic atom-probe analysis

Abstract

The capabilities of the newly developed Tomographic Atom-Probe have been used to study G-phase precipitates in the ferritic phase of duplex stainless steels aged 30 000 hours at 400 °C. It is shown, on three dimensional reconstructions in real space, that G-phase particles form at the interface between the domains produced by the Fe-Cr spinodal decomposition, namely α (Fe-rich) and α’ (Cr-rich). Furthermore, thanks to the instrument very high spatial resolution, the complex internal morphology of these particles can be studied, in particular the partitioning of the various chemical species.