Influence of injected interstitials on α′ precipitation in Fe-Cr alloys under self-ion irradiation

Depending on the particle used to irradiate Fe-Cr alloys, at the same dose and temperature, alpha' precipitation may occur or not. This paper aims at explaining the origin of the absence of alpha' precipitation under ion irradiation. A Fe-15at.% Cr alloy was irradiated with 2 MeV Fe2+ ions at 300 degrees C and analysed using atom probe tomography. For the first time to our knowledge, alpha' particles were observed under ion irradiation. The characterisation of the alpha/alpha' decomposition with depth showed that injected Fe strongly reduced alpha' precipitation. They might have played a major role in the absence of alpha' precipitation under ion irradiation. [GRAPHICS] IMPACT STATEMENT This paper reports the first observation of alpha' precipitation in Fe-Cr alloys after heavy ion irradiation and demonstrates that the injected interstitial effect drastically modifies the precipitation behaviour.