Atom probe tomography of reactor pressure vessel steels: An analysis of data integrity

• Published in: Ultramicroscopy 2011-05, Vol.111 (6), p.676-682
• Main Authors: Hyde, J.M., Burke, M.G., Gault, B., Saxey, D.Wf, Styman, P., Wilford, K.B., Williams, T.J.
• Format: Article
• Language: English
• Subjects: Atom probe analysis; Atom probe tomography; Data integrity; Dislocations; Experimental artefacts; Grain boundaries; Nuclear reactors; Pressure vessels; Reactor pressure vessel steels; Reactors; Steels; Tomography
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2010.12.033

In this work, the importance of optimising experimental conditions for the analysis of reactor pressure vessel (RPV) steels using atom probe tomography is explored. The quality of the resultant atom probe data is assessed in terms of detection efficiency, noise levels and mass resolution. It is demonstrated that artefacts can exist even when experimental conditions have been optimised. In particular, it is shown that surface diffusion of some minority species, including P and Si, to major poles prior to field evaporation can be an issue. The effects were most noticeable during laser pulsing. The impact of surface migration on the characterisation of dislocations and grain boundaries is assessed. The importance of selecting appropriate regions of the reconstructed data for subsequent re-analysis is emphasised. ► The integrity of atom probe data (LEAP-3000X HR) from reactor pressure vessel steels was assessed in terms of detection efficiency, noise levels and mass resolution. ► Fourier transforms were used to determine plane spacings in several crystallographic directions. ► Laser pulsing results in preferential evaporation of Cu and surface diffusion of some minority species, including P and Si, to major poles prior to field evaporation. ► These effects are less evident during voltage pulsing.