Study on hydrogen embrittlement and dynamic strain ageing on low-alloy reactor pressure vessel steels

G. S. Rao, Y. Yagodzinskyy, Z. Que*, P. Spätig, H. P. Seifert

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Tensile tests in air with hydrogen pre-charged smooth specimens and slow strain rate tests with smooth and notched specimens in hydrogenated high-temperature water (HTW) at elevated temperatures (250−288 °C) on low-alloy reactor pressure vessel (RPV) steels revealed a softening in strength and a pronounced reduction in ductility, where the magnitude of hydrogen embrittlement (HE) increased with the dynamic strain ageing (DSA) susceptibility of the RPV steels. In hydrogen pre-charged specimens and in hydrogenated HTW, shear dominated transgranular fracture by microvoid coalescence with increasing amounts of macrovoids, quasi-cleavage regions and secondary cracking were observed. Thermal desorption spectroscopy showed an increase in the concentration of trapped hydrogen in high binding energy traps (vacancies & voids) induced by straining in DSA regime. The observed hydrogen effects on fracture behaviour is a consequence of plasticity localization resulting from the interaction between DSA and hydrogen. HESIV and HELP are the dominant HE mechanisms.

Original languageEnglish
Article number153161
Number of pages13
JournalJournal of Nuclear Materials
Volume556
Early online date4 Jul 2021
DOIs
Publication statusE-pub ahead of print - 4 Jul 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • Dynamic strain ageing
  • Hydrogen embrittlement
  • Low-alloy steel
  • Reactor pressure vessel
  • Thermal desorption spectroscopy

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