Fracture behaviour of the 14Cr ODS steel exposed to helium and liquid lead

0480409 - ÚFM 2018 RIV NL eng J - Journal Article
Hojná, A. - Di Gabriele, F. - Hadraba, Hynek - Husák, Roman - Kuběna, Ivo - Rozumová, L. - Bublíková, P. - Kalivodová, J. - Matějíček, Jiří
Fracture behaviour of the 14Cr ODS steel exposed to helium and liquid lead.
Journal of Nuclear Materials. Roč. 490, JUL (2017), s. 143-154. ISSN 0022-3115. E-ISSN 1873-4820
R&D Projects: GA ČR(CZ) GA14-25246S; GA ČR(CZ) GA14-12837S; GA MŠMT(CZ) LQ1601
Institutional support: RVO:68081723 ; RVO:61389021
Keywords : Impact fracture * Microanalysis * Nanostructured steel * Oxidation * Thermal ageing
OECD category: Materials engineering; Materials engineering (UFP-V); Materials engineering (UFM-A)
Impact factor: 2.447, year: 2017

This work describes the fracture behaviour of the 14Cr ODS steel produced by mechanical alloying process, after high temperature exposures. Small specimens were exposed to helium gas in a furnace at 720 degrees C for 500 h. Another set of specimens was exposed to flowing liquid lead in the COLONRI II loop at 650 degrees C for 1000 h. All specimens were tested for the impact and tensile behaviour. The impact test results are compared to other sets of specimens in the as received state and after isothermal annealing at 650 degrees C for 1000 h. The impact curves of the exposed materials showed positive shifts on the transition temperature. While the upper shelf value did not change in the Pb exposed ODS steel, it significantly increased in the He exposed one. The differences are discussed in terms of surface and subsurface microscopy observation. The embrittlement can be explained as the effect of a slight change in the grain boundary and size distribution combined with the depletion of sub-surface region from alloying elements forming oxide scale on the surface.
Permanent Link: http://hdl.handle.net/11104/0276865