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International audienceThe heterogeneous precipitation of NbC in ferrite has been quantitatively characterised by Transmission Electron Microscopy in a Fe-C-Nb model alloy for different isothermal heat treatments. Elongation and size distribution of precipitates have been derived from Dark Field imaging. For each precipitation states, the precipitation of NbC is occurring on dislocations due to the as-quenched state. This precipitation mechanism leads to characteristic arrays of precipitates in which precipitates grow in a self-similar manner. A detailed study of these arrays has shown that most dislocations decorated by these arrays are edge dislocations with <112> type line vectors. There is only one variant on a given dislocation. This selection can be interpreted by the interaction between dislocation and precipitate strain fields

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I. (2016) Linear chemically sensitive electron tomography using DualEELS and dictionary-based compressed sensing. Ultramicroscopy.There may be differences between this version and the published version. You are advised to consult the publisher's version if you wish to cite from it.http://eprints.gla.ac.uk/122396/ A B S T R A C TWe have investigated the use of DualEELS in elementally sensitive tilt series tomography in the scanning transmission electron microscope. A procedure is implemented using deconvolution to remove the effects of multiple scattering, followed by normalisation by the zero loss peak intensity. This is performed to produce a signal that is linearly dependent on the projected density of the element in each pixel. This method is compared with one that does not include deconvolution (although normalisation by the zero loss peak intensity is still performed). Additionally, we compare the 3D reconstruction using a new compressed sensing algorithm, DLET, with the well-established SIRT algorithm. VC precipitates, which are extracted from a steel on a carbon replica, are used in this study. It is found that the use of this linear signal results in a very even density throughout the precipitates. However, when deconvolution is omitted, a slight density reduction is observed in the cores of the precipitates (a so-called cupping artefact). Additionally, it is clearly demonstrated that the 3D morphology is much better reproduced using the DLET algorithm, with very little elongation in the missing wedge direction. It is therefore concluded that reliable elementally sensitive tilt tomography using EELS requires the appropriate use of DualEELS together with a suitable reconstruction algorithm, such as the compressed sensing based reconstruction algorithm used here, to make the best use of the limited data volume and signal to noise inherent in core-loss EELS.