Observation of Mn-Ni-Si-rich features in thermally-aged model reactor pressure vessel steels

Jenkins, Benjamin M.; Styman, Paul; Riddle, Nick; Bagot, P.A.J.; Moody, Michael P.; Smith, George Adam; Hyde, J.M.

doi:10.1016/j.scriptamat.2020.09.029

Cited by 9 publications

(1 citation statement)

References 30 publications

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“…In favor of this theory is the fact that the thermal stability of NSM precipitates in RPV steels at locally low Fe content and the presence of irradiation-induced radiation defects [41] was predicted by thermodynamic models and simulations [36,42] and confirmed experimentally [40,43,44]. The stability of NSM precipitates has been confirmed both indirectly by annealing irradiated samples at a higher temperature (425 • C), as a result of which some precipitates are preserved and enlarged [43], and directly after long isothermal exposures at temperatures in the range of 330-405 • C, when their formation is observed [45]. Despite the thermodynamic stability of precipitates (G and Γ2 phases), in the absence of a sufficient amount of Cu at RPV operating temperatures, the driving force for the formation of NSM precipitates is small, and their homogeneous nucleation of precipitates in a defect-free matrix is hampered.…”

Section: High-cu Materialssupporting

confidence: 59%

The Effect of Operational Factors on Phase Formation Patterns in the Light-Water Reactor Pressure Vessel Steels

Fedotova,

Kuleshova

2023

Metals

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This paper presents the results of atom probe tomography studies on radiation-induced phase formation in light-water reactor pressure vessel steels after neutron irradiation under various conditions in comparison with the literature data. The given irradiation conditions are fluence (10–100) × 1022 m−2, flux (5–2700) × 1014 m−2s−1 and irradiation temperature (50–400) °C. The composition of the studied steels varies in a wide range for the elements significantly affecting radiation and thermal resistance of steels: Ni in the range of 0.2–6.0 wt.%, Mn–0.03–1.1 wt.%, Cu–0.01–0.16 wt.%, and P–0.01–0.03 wt.%. The number density, volume fraction, size, composition, and nucleation sites of precipitates are determined. The regularities of the effect of various operational factors on the phase formation in these steels have been analyzed and revealed. The study shows that in materials with high copper content, Cu-rich precipitates are formed by a radiation-enhanced mechanism. In materials with low copper content, their formation upon irradiation at 300 °C occurs by a radiation-induced mechanism since the main nucleation sites are point defect clusters formed in cascades. At the same time, the density, volume fraction, and composition of the precipitates depend on the steel composition (Ni and Mn content). In the steel with increased Ni content up to 5 wt.% but with ultra-low Mn content ≤ 0.03 wt.%, it is possible to suppress the formation of Ni-Si-Mn precipitates under irradiation.

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