Effects of Cr content on ion-irradiation hardening of FeCrAl ODS ferritic steels with 9 wt\% Al

FeCrAl ODS steels for accident tolerant fuel claddings are designed to bear high-Cr and Al for enhancing oxidation resistance. In this study, we investigated the effects of Cr content on ion-irradiation hardening of three ODS ferritic steels with different Cr contents added with 9 wt\% Al, Fe12Cr9Al (SP12), Fe15Cr9Al (SP13), and Fe18Cr9Al (SP14). The specimens were irradiated with 6.4MeV Fe\textsuperscript{3+} at 300 \textdegree C to nominal 3 dpa. The irradiation hardening was measured by nanoindentation method, and the Nix-Gao plots were used to evaluate the bulk-equivalent hardness. The results showed that the irradiation hardening decreased with increasing Cr content. The reason is due to the growth of dislocation loops hindered by solute Cr atoms. TEM observations showed both $\langle 100\rangle$ and $1/2\langle 111\rangle$ dislocation loops existed in the irradiated area. The irradiation hardening was estimated by dispersed barrier hardening (DBH) model with dislocation loops.