Nano-oxide precipitation kinetics during the consolidation process of a ferritic oxide dispersion strengthened steel.

International audienceOxide Dispersion Strengthened (ODS) steels are candidates for nuclear applications. ODS are produced by mechanical alloying of Fe-14Cr, Y2O3 and TiH2 powders and consolidation at 1100°C, resulting in finely dispersed nano-oxides. Their precipitation kinetics has been quantitatively determined by in-situ Small Angle X-ray Scattering during continuous heating up to 1100°C. Clusters, found in the as-milled state start growing at 450°C until 1100°C, while almost no coarsening was recorded during subsequent isothermal annealing. The nano-oxides resulting from these in-situ experiments were found to be representative of those in materials processed by hot isostatic pressing and hot extrusion. Graphical abstract Main matter Ferritic Oxide Dispersion Strengthened (ODS) steels were developed for applications where a good resistance to harsh environment is required such as generation IV nuclear fission [1] or nuclear fusion power plants [2]. Their Fe-Cr ferritic matrix gives them a good swelling resistance under irradiation [3,4] as well as a good corrosion resistance [5,6]. Nano-precipitates of Y-Ti-O lead to high yield strength and high improvement of thermal creep resistance [7-10] as these nano-oxides act as strong pinning points for both grain boundaries and dislocations, even at high temperatures [7-9,11-13]