Microstructural stability of ODS Fe–14Cr (–2W–0.3Ti) steels after simultaneous triple irradiation

•Two Fe14Cr ODS steels have been simultaneously triple ion-beam irradiated.•Their microstructural stability has been analyzed using TEM techniques.•Nanoparticles maintain composition and morphology while sizes increase slightly. Simultaneous triple-ion beam irradiation experiments with Fe5+, He+ and H+ ions were performed to simulate fusion damage on two nanostructured ferritic alloys with nominal composition Fe–14Cr–0.3Y2O3 and Fe–14Cr–2W–0.3Ti–0.3Y2O3. Samples were irradiated at 600°C to an estimated dose of ∼ 30dpa, 600appm He, 1500appm H, and the effects on the microstructure of these alloys investigated by analytical transmission electron microscopy. The results reveal the development of nanovoids, or small bubbles, undetected in the unirradiated samples, and a virtual compositional stability of the dispersion. Nevertheless, upon irradiation the measured size distribution indicates a slight growth of those dispersoids having the smaller sizes.