Microstructural characteristics and embrittlement phenomena in neutron irradiated 309L stainless steel RPV clad

J. S. Lee, I. S. Kim, R. Kasada, A. Kimura

研究成果: ジャーナルへの寄稿学術論文査読

18 被引用数 (Scopus)

抄録

The effects of neutron irradiation on the microstructural features and mechanical properties of 309L stainless steel RPV clad were investigated using TEM, SEM, small tensile, microhardness and small punch (SP) tests. The neutron irradiations were performed at 290 °C up to the fluences of 5.1×1018 and 1.02×1019 n/cm2 (>1 MeV) in Japan Materials Testing Reactor (JMTR). The microstructure of the clad before and after irradiation was composed of main part of fcc austenite, a few percent of bcc δ-ferrite and small amount of brittle σ phase. After irradiation, not only the yield stress and microhardness, but SP ductile to brittle transition temperature (SP-DBTT) were increased. However, the increase in SP-DBTT is almost saturated, independent of the neutron fluence. Based on the TEM observation, the origin of irradiation hardening was accounted for by the irradiation-produced defect clusters of invisible fine size (<1-2 nm), and the shift of SP-DBTT was primary due to the higher hardening and the preferential failure of δ-ferrite. The embrittlement of the clad was strongly affected by the initial microstructural factors, such as the amount of brittle σ phase, which caused a cracking even in an early stage of deformation.

本文言語英語
ページ(範囲)38-46
ページ数9
ジャーナルJournal of Nuclear Materials
326
1
DOI
出版ステータス出版済み - 2004 3月 1

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