The presence of Al in Fe-Mn-C based multi-component steels induces precipitate formation whose size, number density and distribution can be varied depending on the thermomechanical processing conditions. Further alloying of such steels with Ni promotes the formation of Ni-Al type B2 precipitates depending on the Mn content.

This work therefore attempts to analyse correlatively the structure of nano-scale precipitates formed in a duplex (i.e. FCC matrix and embedded BCC precipitates) steel along with their precise local chemical composition in a high statistical manner.

To achieve the above, a custom designed correlative microscopy platform was utilised in a Scanning Electron Microscope enabling imaging in transmission geometry combined with transmission Kikuchi diffraction for structure analysis while the precise local chemical composition at near atomic-resolution was obtained from the same investigated volume using Atom Probe Tomography.

This correlative methodology applied to hot rolled and annealed conditions, provided deeper insights into the role of starting microstructures on the precipitation kinetics and hence on the final mechanical properties of the steel. Further, alloying of Boron on the improvement in grain boundary cohesion of these steels will be highlighted.