Hardening and microstructural evolution of A533b steels irradiated with Fe ions and electrons

Watanabe, Hideo; Arase, Satoko; Yamamoto, Takuya; Wells, Peter; Onishi, Taku; Odette, G.R.

doi:10.1016/j.jnucmat.2015.12.045

Cited by 18 publications

(4 citation statements)

References 28 publications

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“…The alloy was neutron irradiated to a fluence (E > 1 MeV) of 6.3×10 19 n cm -2 at a flux of 1.0×10 14 at ≈ 300˚C, and to a fluence of 1.4×10 20 n cm -2 at a flux of 3.6×10 12 n cm -2 s -1 at ≈ 290°C, in the Belgian Reactor 2 (BR2) and the US Advanced Test Reactor (ATR), respectively [14]. The precipitates observed in these alloy/irradiation conditions are fully representative of those in other Cu bearing steels with medium to high Ni contents for a wide range of irradiation and aging conditions [14,[22][23][24].…”

Section: Methodsmentioning

confidence: 71%

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Shu¹,

Wells²,

Almirall³

et al. 2018

Acta Materialia

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What determines precipitate morphologies in co-precipitating alloy systems? We focus on alloys of two precipitating phases, with the fast-precipitating phase acting as heterogeneous nucleation sites for a second phase manifesting slower kinetics. Kinetic lattice Monte Carlo simulations show that the interplay between interfacial and ordering energies, plus active diffusion paths, strongly affect the selection of core-shell verses appendage morphologies. We study a FeCuMnNiSi alloy using the combination of atom probe tomography and simulations, and show that the ordering energy reduction of the MnNiSi phase heterogeneously nucleated on a pre-existing copper-rich precipitate exceeds the energy penalty of a predominantly Fe/Cu interface, leading to initial appendage, rather than core-shell, formation. Diffusion of Mn, Ni and Si around and through the Cu core towards the ordered phase results in subsequent appendage growth. We further show that in cases with higher primary precipitate interface energies and/or suppressed ordering, the coreshell morphology is favored.3

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Section: Methodsmentioning

confidence: 71%

Thermodynamics and kinetics of core-shell versus appendage co-precipitation morphologies: An example in the Fe-Cu-Mn-Ni-Si system

Shu¹,

Wells²,

Almirall³

et al. 2018

Acta Materialia

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“…The discrepancy is possibly caused by the timedependent sink strength treated by Soisson et al [97], whereas our model considered a steady-state condition. It should also be noted their cluster dynamics modeling of defect clusters [97] did not consider the potential overlap or spatial exclusion by other defect clusters which causes the matrix frustration [98] or volume exclusion [99,100] effect. This effect may become important when the defect cluster density is high, particularly under high-flux heavy-ion irradiation.…”

Section: Potential Applications Limitations and Insights Of The Modelmentioning

confidence: 99%

Flux effects in precipitation under irradiation – Simulation of Fe-Cr alloys

Reese

Marquis

et al. 2019

Acta Materialia

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Radiation-enhanced precipitation of Cr-rich α' in irradiated Fe-Cr alloys, which results in hardening and embrittlement, depends on the irradiating particle and the displacement per atom (dpa) rate. Here, we utilize a Cahn-Hilliard phase-field based approach, that includes simple models for nucleation, irradiating particle and rate dependent radiation-enhanced diffusion and cascade mixing to simulate α' evolution under neutrons, heavy ions, and electron irradiations. Different irradiating particles manifest very different cascade mixing efficiencies. The model was calibrated using neutron data. For cascade inducing neutron/heavy-ion dpa rates at 300 °C between 10 -8 and 10 -6 dpa/s the model predicts approximately constant number density, decreasing radius, decreasing α' Cr composition, and lower α' volume fraction. The model then predicts a dramatic transition to no α'formation above approximately 10 -5 dpa/s, while electron irradiation, with weak mixing, had little effect at dpa rates up to 10 -3 dpa/s. These model predictions are consistent with experiments. We explain the results in terms of the flux dependence of the radiation enhanced diffusion, cascade mixing, and their ratio, which all vary significantly in relevant flux ranges for neutron and cascade inducing ion irradiations. These results show that both cascade mixing and radiation enhanced diffusion must be accounted for when attempting to emulate neutron-irradiation effects using accelerated ion irradiations. flux effects by triple-beam ions at 450 °C to 10 dpa [17]. Pareige et al. recently reported an APT study of Fe-12Cr under heavy-ion irradiation at 1×10 -4 dpa/s at 300 °C that observed a low density of dilute Cr clusters after irradiation to 0.5 dpa [18]. Likewise, Marquis et al. [19] found no α' in Fe-15Cr irradiated by Fe ++ ions at a dose rate of 1×10 -4 dpa/s up to 60 dpa at 300 °C, but observed a small density clusters with only 35-50 at.% Cr in in a Fe-15Cr at a lower dose rate of ≈ 1×10 -5 dpa/s, suggesting a pronounced dose rate effect [19]. Korchuganova et al. carried out a heavy-ion irradiation at room temperature on a Fe-22Cr alloy that was pre-aged at 500 °C to form α' precipitates with a distribution of sizes [20]. APT showed that the heavy-ion irradiation dissolved the small preexisting α' precipitates and made the larger ones more diffuse. A similar effect of heavy-ion irradiation was also shown to retard spinodal decomposition of Cr-rich α' in a duplex stainless steel with 20 wt.% Cr at 300 °C [21]. In contrast to the heavy-ion irradiation microstructures, Tissot et al. reported that a 3.9×10 -5 dpa/s electron irradiation at 300 °C accelerated precipitation of near equilibrium α' [22]. Accelerated α' precipitation under neutron irradiation has been attributed to radiation-enhanced diffusion (RED). RED depends on both temperature and dose rate due to the corresponding effect on vacancy and self-interstitial atom recombination mediated concentrations through a variety of mechanisms. However, a dose rate effect on RED does not full...

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“…When the solute clusters transform into brittle compounds such as silicides, they would serve as the nucleation sites of microcracks by particle cracking. The G-phase (Ni 16 Si 7 Mn 6 ) is a possible configuration for the NieSieMn clusters [22]; hence, the critical condition by which the NieSieMn clusters transform into the G-phase is of particular interest in the nuclear materials research community as a guide line of microstructure-based embrittlement modeling.…”

Section: Introductionmentioning

confidence: 99%