Post-irradiation annealing behaviour of oxide dispersion strengthened Fe-Cr alloys studied by nanoindentation

ABSTRACT

To study the nature of irradiation-induced nanofeatures in oxide dispersion strengthened (ODS) Fe-Cr alloys, post-irradiation isochronal thermal annealing up to 600°C was performed for ODS Fe-9%Cr and Fe-14%Cr alloys ion-irradiated at 300°C and 500°C. Nanoindentation indicated hardening for all as-irradiated alloys and complete hardness recovery upon post-irradiation annealing. Cross-sectional TEM indicated an irradiation-induced defect band near peak damage mainly consisting of dislocation loops. Candidate mechanisms of recovery were critically evaluated. Shrinkage of loops via capture of thermal vacancies was found to correctly reflect the annealing behaviour of ODS Fe-9Cr irradiated at 300°C.

KEYWORDS:

• ODS steel
• ion irradiation
• post-irradiation annealing
• nanoindentation
• TEM

Acknowledgements

Access to the Ion Beam Center and the TEM facilities of HZDR is acknowledged. We wish to thank René Hübner for assistance with the TEM and Annette Kunz for FIB sample preparation.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Frank Bergner http://orcid.org/0000-0002-4058-1044

Additional information

Funding

This work was supported by the FP7 Nuclear Fission, Safety and Radiation Protection project MatISSE [grant agreement number 604862]. The first author appreciates funding from the China Scholarship Council. The TEM Talos was funded by the German Federal Ministry of Education and Research (BMBF) [grant agreement number 03SF0451].