Integrated modeling of helium-vacancy clustering in Eurofer97 steel upon He+/Fe3+ dual-beam irradiation

Abstract By developing an integrated rate theory model, we studied helium-vacancy (He-V) clustering in ferritic/martensitic Eurofer97 steels under He+/Fe3+ dual-beam irradiation. Different from the known single peak concentration profile of total atomic He, the concentration of ‘solute’ He atom (interstitial He) increases and decreases twice during irradiation, showing two peaks as a function of irradiatiom time (dose). The second increase in concentration was caused by the operation of the kick-out mechanism aided by irradiation-induced self-interstitials. We show that the kicked-out interstitial He enhances the growth of He-V clusters and leads to the shift of cluster pressurization states. He-V clustering direction is also governed by the kicked-out interstitial He.