Abstract

Nuclear Reactor Environments Are Extreme in Nature Due to the Combination of Exposure to Corrosive Coolant, Mechanical Stresses, and Neutron Irradiation Damage. This Combination of Environments Can Lead to Irradiation Induced/assisted Precipitation, Segregation, and Embrittlement Coupled with Enhanced Creep and Stress Corrosion Cracking. While Nanostructured Materials Are of Interest in a Variety of Applications Due to their Unique Properties Including High Mechanical Strength, for Nuclear Applications Nanostructured Materials Have the Added Benefit of Irradiation Resistance Due to the High-Volume Density of Sinks for Irradiation-Induced Defects. in This Study, We Show Unique Radiation-Induced Segregation (RIS) Behavior in Nanocrystalline 304 Stainless Steel (SS304). Typical RIS in Austenitic Steels Includes Ni Enrichment and Cr Depletion within the Grain Boundaries. in Nanostructured SS304 This RIS is Reduced. Furthermore, Interestingly, Some Grain Boundaries in the Nanocrystalline SS304 in This Study Were Found to Be Enriched in Cr after Fe2+ Ion Irradiation at 500 °C Up to 50 Displacements Per Atom (Dpa). to Understand This Unique Observation, Lattice-Based Atomic Kinetic Monte Carlo Simulations Were Performed to Investigate the Effects of Grain Size, Thermal Segregation, as Well as Injected Interstitials (Introduced as Fe Self-Ions). the Results Indicate that the Cr Enrichment at Grain Boundaries May Be Caused by Combined Effects of Grain Size, Self-Ion Injection and Preferential Cr Diffusion Via the Interstitial Mechanism. the Findings Also Suggest a Possible Difference in RIS between Ion and Neutron Irradiations.

Department(s)

Materials Science and Engineering

Comments

U.S. Department of Energy, Grant DE-NE0008524

Keywords and Phrases

Austenitic steel; Grain boundary; Grain size effect; Ion implantation; Radiation-induced segregation

International Standard Serial Number (ISSN)

1359-6454

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2023 Elsevier; Acta Materialia, All rights reserved.

Publication Date

01 Mar 2023

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