Void swelling in binary Fe-Cr alloys at 200 DPA

摘要

Microstructural examinations have been performed on a series of binary Fe-Cr alloys irradiated in the FFTF/MOTA at 425C to 200 dpa. The data represent the highest swelling levels reported in neutron irradiated ferritic alloys. The alloy compositions ranged from 3 to 18% Cr in 3% Cr increments, and the irradiation temperature corresponded to the peak swelling condition for this alloy class. Density measurements showed swelling levels as high as 7.4%, with the highest swelling found in the Fe-9Cr and Fe-6Cr alloys. Microstructural examinations revealed that the highest swelling conditions contained well-developed voids, often as large as 100 nm, and a dislocation network comprised of both (sub 2)(sup a)<111> and a<100> Burgers vectors. Swelling was lower in the other alloys, and the swelling reduction could be correlated with increased precipitation. These results are considered in light of current theories for low swelling in ferritic alloys, but no theory is available to completely explain the results.