Abstract

The influence of grain size, irradiation temperature, and dose on the evolution of irradiation-induced defects in austenitic 304L stainless steel (SS) was systematically investigated. Coarse-grained (CG), ultrafine-grained (UFG), and nanocrystalline (NC) specimens were exposed to irradiation doses up to 10 displacements per atom (dpa) at room temperature (RT), 300°C, and 500°C. Dislocation loop size and density were quantitatively analyzed using transmission electron microscopy, and results showed that the dislocation loop size remained comparable across different grain sizes. However, loop density was strongly dependent on the grain size. The CG specimens exhibited the highest loop density due to a limited fraction of defect sinks, while NC specimens showed superior radiation resistance. The loop densities in NC specimens were approximately an order of magnitude lower than those in CG specimens. Furthermore, NC samples retained nanocrystalline grain sizes across all temperatures and irradiation doses, indicating excellent thermal and irradiation stability. The findings underscore the critical role of grain boundaries as defect sinks and highlight nano structuring as an effective strategy to enhance radiation tolerance in structural materials.

Department(s)

Mechanical and Aerospace Engineering

International Standard Serial Number (ISSN)

1543-1851; 1047-4838

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Springer; Minerals, Metals and Materials Society (TMS), All rights reserved.

Publication Date

01 Jan 2025

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