Microstructural characterization of the synergic effects of dynamic strain ageing and hydrogen on fracture behaviour of low-alloy RPV steels in high-temperature water environments

0536181 - ÚFM 2021 RIV US eng J - Journal Article
Que, Z. - Heczko, Milan - Kuběna, Ivo - Seifert, H. P. - Spätig, P.
Microstructural characterization of the synergic effects of dynamic strain ageing and hydrogen on fracture behaviour of low-alloy RPV steels in high-temperature water environments.
Materials Characterization. Roč. 165, JUL (2020), č. článku 110405. ISSN 1044-5803. E-ISSN 1873-4189
R&D Projects: GA MŠMT LM2015069
Institutional support: RVO:68081723
Keywords : assisted cracking * tensile behavior * resistance * deformation * degradation * toughness * sulfur * Dynamic strain ageing * Hydrogen embrittlement * Scanning transmission electron microscopy * Fracture resistance * Low-alloy steel * Plasticity localization
OECD category: Materials engineering
Impact factor: 4.342, year: 2020
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S1044580320311670?via%3Dihub

Tensile tests in high-temperature air with pre-charged hydrogen and elastic plastic fracture mechanics tests in hydrogenated high-temperature water (HTW) at 250 and 288 degrees C on low-alloy reactor pressure vessel (RPV) steels revealed a clear but moderate reduction of ductility and fracture resistance, respectively. The observed behaviour is a consequence of synergistic effects between hydrogen embrittlement (HE) and the dynamic strain ageing (DSA), in which the HE was amplified by a high DSA susceptibility. The deformation microstructures in the vicinity of the crack tips in air and HTW of two RPV steels with high DSA susceptibility were characterized in detail. These investigations support the idea that the environmental degradation of fracture resistance in hydrogenated HTW was mainly due to the plasticity localization by the interaction between DSA and hydrogen in RPV steels. Synergistic effects of DSA and hydrogen lead to heterogeneous distribution of dislocations and formation of dislocation cells inside bainitic laths.
Permanent Link: http://hdl.handle.net/11104/0314008