Dose and compositional dependence of irradiation-induced property change in FeCr

• Main Authors: Song, Kay, Sheyfer, Dina, Mizohata, Kenichiro, Zhang, Minyi, Liu, Wenjun, Gürsoy, Doğa, Yang, David, Tolkachev, Ivan, Yu, Hongbing, Armstrong, David E J, Hofmann, Felix
• Format: Journal Article
• Language: English
• Published: 01-08-2023
• Subjects: Physics - Materials Science
• DOI: 10.48550/arxiv.2308.00771

Ferritic/martensitic steels will be used as structural components in next
generation nuclear reactors. Their successful operation relies on an
understanding of irradiation-induced defect behaviour in the material. In this
study, Fe and FeCr alloys (3-12%Cr) were irradiated with 20 MeV Fe-ions at 313
K to doses ranging between 0.00008 dpa to 6.0 dpa. This dose range covers six
orders of magnitude, spanning low, transition and high dose regimes. Lattice
strain and hardness in the irradiated material were characterised with
micro-beam Laue X-ray diffraction and nanoindentation, respectively.
Irradiation hardening was observed even at very low doses (0.00008 dpa) and
showed a monotonic increase with dose up to 6.0 dpa. Lattice strain
measurements of samples at 0.0008 dpa allow the calculation of equivalent
Frenkel pair densities and corrections to the Norgett-Robinson-Torrens (NRT)
model for Fe and FeCr alloys at low dose. NRT efficiency for FeCr is 0.2, which
agrees with literature values for high irradiation energy. Lattice strain
increases up to 0.8 dpa and then decreases when the damage dose is further
increased. The strains measured in this study are lower and peak at a larger
dose than predicted by atomistic simulations. This difference can be explained
by taking temperature and impurities into account.