Swelling and microstructure of pure Fe and Fe-Cr alloys after neutron irradiation to ∼26 dpa at 400 °C

The microstructures of pure Fe and various Fe-Cr binary alloys in both the annealed and heavily cold worked conditions were investigated after irradiation to 25.8 dpa at 4 x 10(-7) dpa s(-1) in the BR-10 fast reactor. Microscopy has shown that the largest swelling of 4.5% was observed in the cold worked pure iron while that of annealed Fe is only 1.7%. Additions of 2% chromium resulted in a decrease of swelling, but the swelling of cold worked Fe-2Cr alloy was still higher than that of the annealed condition. Independent of the initial starting condition, swelling in the Fe-6Cr alloy was completely suppressed. In alloys with higher chromium content swelling of 0.04-0.05% was observed only in samples irradiated in the annealed condition. There were also significant changes in dislocation and precipitate microstructure. Published by Elsevier B.V.