Thermal ageing effect on solute segregation and precipitation in the heat-affected-zone of dissimilar metal welds for nuclear power plants.
In: Materials & Design, Jg. 232 (2023-08-01), S. N.PAG
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Zugriff:
[Display omitted] • Segregation and precipitation in the heat affected zone of dissimilar metal welds have been quantitatively determined after long-term thermal ageing. • Co-segregation of 9 elements on extended defects has been quantified at the atomic scale by Atom Probe Tomography versus ageing. • P segregation is kinetically limited and predicted to stay low up to the end of the EPRTM reactor service. • The formation of Cu-rich clusters on extended defects is only observed in the aged samples. • Solute co-segregation and Cu-rich precipitate formation are associated with the evolution of mechanical properties with thermal ageing. Solute segregation in the carbon-depleted (CDZ) heat-affected zone of dissimilar metal welds (DMW) designed for nuclear power plant EPRTM reactors has been investigated by atom probe tomography (APT) and related to the mechanical properties (toughness test). The analysis of grain boundaries (GBs) by APT allowed the quantification of the P segregation and other solute elements, in all the analyzed samples, before and after long-term ageing heat treatments. The post-weld stress-relief heat treatment applied to the samples before the ageing heat treatments leads to important GBs segregation levels. Following thermal ageing treatments allow a relative increase of GB segregation. P segregation increases with the various thermal ageing conditions. The experimental data were used to model P segregation in high-angle GBs. The simulations show that P segregation is kinetically limited by bulk diffusion, explaining the observed P segregation increase with temperature. P segregation in GBs in the CDZ of the DMW should remain low compared to the expected equilibrium segregation level during the entire reactor service. In addition to solute segregation in extended defects, APT measurements revealed the presence of Cu-rich clusters in GBs, dislocations, and grains in all the aged samples. These clusters were not observed in the sample before ageing. [ABSTRACT FROM AUTHOR]
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Thermal ageing effect on solute segregation and precipitation in the heat-affected-zone of dissimilar metal welds for nuclear power plants.
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Autor/in / Beteiligte Person: | Medouni, I. ; Portavoce, A. ; Maugis, P. ; Descoins, M. ; Yescas, M. ; Roch, F. ; Joly, P. ; Hoummada, K. |
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Zeitschrift: | Materials & Design, Jg. 232 (2023-08-01), S. N.PAG |
Veröffentlichung: | 2023 |
Medientyp: | academicJournal |
ISSN: | 0264-1275 (print) |
DOI: | 10.1016/j.matdes.2023.112158 |
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