“Contextualizing dispersoid evolution within the microstructure of MA956 using ion irradiation”

• DOI: 10.1016/j.nme.2021.101024
• Publication Date: 2021-05-13T16:22:12Z
• Authors: E. Getto; N. Nathan; J. McMahan; B. Baker; S. Taller
• Keywords: Number density; Void (composites)

Determining the microstructure evolution of oxide dispersion-strengthened (ODS) alloys is important for predicting safety and structural integrity fast reactors. In particular, understanding co-evolution dispersoids with dislocation loops network critical a comprehensive response to radiation. Ion irradiations were performed on dispersion strengthened MA956 5 MeV Fe++ ions from 400 500 °C at doses ranging 50 200 dpa. Characterization was primarily scanning transmission electron microscopy energy-dispersive x-ray spectroscopy investigate Y-Al-O dispersoids, voids dislocations. Regardless temperature, increased in diameter decreased number density, which attributed an Ostwald coarsening mechanism supported by calculations radiation enhanced diffusion ballistic dissolution. demonstrated excellent void swelling resistance did not form except 450 °C, dpa where nucleated upon dispersoids. The loop highest followed then while density tended decrease dose. behavior explained as function evolving defect kinetics, utilizing rate theory calculate point concentrations increasing diffusivity vacancies. At interstitials had high enough nucleate new but vacancies remained relatively immobile. are able annihilate due non-negligible mutual recombination causing loops. vacancy both mobile coalesce larger provide pathway solutes diffusing