Compositional dependence of dislocation loop development and microstructures in austenitic Fe-Ni-Cr alloys under proton irradiation

Abstract

In order to examine the compositional dependence of dislocation loops and other microstructural changes under irradiation in austenitic Fe-Ni-Cr alloys, eight solution-annealed ternary Fe-Ni-Cr alloys whose Ni content varies from 25 to 45 wt% and Cr content from 5 to 15 wt% were irradiated by 200 keV protons at 873 K to 0.4, 1.6 and 15 dpa after helium pre-injection to 10 appm. Dislocation loop diameter increased but loop number density decreased with increasing Ni content and decreasing Cr content. A discernible compositional change of dislocation density was not detected. With increasing Ni content and decreasing Cr content, swelling decreased because of the drastic decrease of void number density. The attachment of dislocation lines to the voids, tiny voids smaller than 3 nm in diameter, and black contrast, which could be the contrast from void embryos smaller than 10 nm in diameter, were observed in the alloys irradiated to 1.6 dpa.