A dislocation dynamics study into the hardening mechanisms in FeCr alloys

Full text of publication follows: Cr-based ferritic steels have been selected as nuclear fusion reactor structural materials for the design and building phases of MCF and ICF reactors. FeCr alloys present good resistance against corrosion and swelling, but may still be subject to considerable hardening and embrittlement under the intense irradiation conditions expected during operation. For the candidate Fe 9-12Cr alloys, irradiation-assisted phase separation might ensue, giving rise to rich microstructures consisting of α precipitates, system dislocations, and irradiation defects. The interplay among these nano-features may impact the normal plastic behavior in the system, leading to hardening. In this work we present a dislocation dynamics study of dislocation interactions with Cr-rich precipitates and irradiation dislocation loops in bcc Fe- 9Cr alloys. The free parameters of our DD methodology are fitted consistently to atomistic results, and the particularities of the dislocation-precipitate interaction are treated in terms of the Eshelby formulation for elliptical inclusions. The relative contribution of each type of irradiation species to the hardening is assessed. (authors)