Enhanced Resistance to Irradiation Induced Ferritic Transformation in Nanostructured Austenitic Steels

Abstract

Irradiation induced phase transformation of γ-austenite to α-ferrite has been observed in austenitic steels for the past several decades. This transformation can be detrimental to structural materials in a nuclear reactor environment as the increased fraction of the ferritic phase can increase corrosion and embrittlement and lead to stress corrosion cracking. This transformation is caused by both strain induced martensite transformation as well as radiation induced segregation and precipitation. In this study, two radiation tolerant nanostructured 304L austenitic steels (one ultrafine grained and one nanocrystalline) were manufactured using severe plastic deformation. These nanostructured 304L steels were compared to conventional coarse-grained 304L, after self-ion irradiation at 500°C up to a peak damage of 50 displacements per atom. Phase fraction after irradiation was analyzed using grazing incidence x-ray diffraction, precession electron diffraction, and electron backscatter diffraction. Nanostructured 304L steels showed significant resistance to irradiation induced austenite to ferrite transformation. This resistance was shown to be due to a decrease in defect formation, as well as a reduction in radiation induced segregation and precipitation.

Department(s)

Materials Science and Engineering

Comments

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

Keywords and Phrases

Austenitic Steels; Irradiation Induced Phase Transformation; Irradiation Induced Precipitation; Irradiation Induced Segregation; Nanostructured Materials; Severe Plastic Deformation

International Standard Serial Number (ISSN)

2589-1529

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 Elsevier, All rights reserved.

Publication Date

01 Sep 2020

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