Radiation tolerance of neutron-irradiated model Fe-Cr-Al alloys

The Fe-Cr-Al alloy system has the potential to form an important class of enhanced accident-tolerant cladding materials in the nuclear power industry owing to the alloy system's higher oxidation resistance in high-temperature steam environments compared with traditional zirconium-based alloys. However, radiation tolerance of Fe-Cr-Al alloys has not been fully established. In this study, a series of Fe-Cr-Al alloys with 10-18 wt % Cr and 2.9-4.9 wt % Al were neutron irradiated at 382 degrees C to 1.8 dpa to investigate the irradiation-induced microstructural and mechanical- property evolution as a function of alloy composition. Dislocation loops with Burgers vector of a/2 < 111 > and a < 100 > were detected and quantified. Results indicate precipitation of Cr-rich alpha' is primarily dependent on the bulk chromium composition. Mechanical testing of sub-size-irradiated tensile specimens indicates the hardening response seen after irradiation is dependent on the bulk chromium composition. A structure property relationship was developed; it indicated that the change in yield strength after irradiation is caused by the formation of these radiation-induced defects and is dominated by the large number density of Cr-rich alpha' precipitates at sufficiently high chromium contents after irradiation. Published by Elsevier B.V.