Mechanical properties and TEM examination of RAFM steels irradiated up to 70dpa in BOR-60

Gaganidze, E.; Petersen, C.; Materna-Morris, E.; Dethloff, C.; Weiß, Oliver; Aktaa, Jarir; Povstyanko, A.V.; Fedoseev, A.; Makarov, O. Yu.; Prokhorov, V.I.

doi:10.1016/j.jnucmat.2010.12.047

Cited by 104 publications

(47 citation statements)

References 14 publications

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“…The effect of irradiation up to 32 dpa has been analyzed in a BOR 60 reactor (Dimitrovgrad) in the framework of ARBOR 1 project [8,16]. The next was ARBOR 2 project, which involved an increase in the irradiation dose to ~70 dpa [17]. The study of the irradiated specimens demonstrated degradation of the mechanical properties under neutron irradiation, i.e., radiation strengthening and therefore the loss of ductility.…”

Section: Introductionmentioning

confidence: 99%

Evolution of microstructure in advanced ferritic-martensitic steels under irradiation: the origin of low temperature radiation embrittlement

et al. 2016

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Advanced reduced activation ferritic/martensitic steels and oxide dispersion-strengthened steels exhibit significant radiation embrittlement under low temperature neutron irradiation. In this study we focused on atom probe tomography (APT) of Eurofer97 and ODS Eurofer steels irradiated with neutrons and heavy ions at low temperatures. Previous TEM studies revealed dislocation loops in the neutron-irradiated f\m steels. At the same time, our APT showed early stages of solid solution decomposition. High density (10 24 m -3 ) of ~3-5 nm clusters enriched in chromium, manganese, and silicon atoms were found in Eurofer 97 irradiated in BOR-60 reactor to 32 dpa at 332°C. In this steel irradiated with Fe ions up to the dose of 24 dpa, pair correlation functions calculated using APT data showed the presence of Cr-enriched pre-phases.APT study of ODS Eurofer found a significant change in the nanocluster composition after neutron irradiation to 32 dpa at 330 °C and an increase in cluster number density. APT of ODS steels irradiated with Fe ions at low temperatures revealed similar changes in nanoclusters.These results suggest that irradiation-induced nucleation and evolution of very small precipitates may be the origin of low temperature radiation embrittlement of f\m steels.

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Section: Introductionmentioning

confidence: 99%

Evolution of microstructure in advanced ferritic-martensitic steels under irradiation: the origin of low temperature radiation embrittlement

et al. 2016

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“…Usually, as the strain and stress amplitudes are increased, the number of fatigue cycles to failure decreases, as shown in Figures 6a and 6b [Gaganidze et al 2011]. Fitting a simple power law expression to this data:…”

Section: Mean and Alternating Stresses Encountered During Fatiguementioning

confidence: 99%

“…The alternating and mean stresses, and the stress ratio, are defined as the respective maximum and minimum levels: Figure 6 -Fatigue cycles to failure as a function of the strain range, for un-irradiated EUROFER97 at 550C [Gaganidze et al 2011]. Note that this curve is for the low-cycle fatigue regime.…”

Section: Mean and Alternating Stresses Encountered During Fatiguementioning

confidence: 99%

“…The effects of radiation-induced hardening can be understood in terms of the evolution of radiation-induced defect density within the material being irradiated [Gaganidze et al 2011]. These radiation-induced defects serve as obstacles impeding glide dislocation.…”

Section: Effect Of Radiation On Strength and Hardnessmentioning

confidence: 99%

“…For example, such lowcycle fatigue data at a test temperature of 300-350C has just appeared in the scientific literature for EUROFER97 and EUROFER07 HT, with irradiation to 0, 31, 47 and 71 dpa, at an irradiation temperature of 300-335C [Gaganidze et al 2011]. The irradiation was done in the BOR-60 sodium-cooled fast reactor in Russia.…”

Section: Effects Of Radiation On Fatigue Life Of Fm Steelsmentioning

confidence: 99%

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Fatigue Life Prediction for Steels in Pulsating Irradiated Systems

Farmer¹,

Kramer²,

Williams³

2012

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EXECUTIVE SUMMARYContinuous energy pulses at a repetition rate of 10 Hz and the use of ferritic-martensitic (FM) steel for construction are assumed for a hypothetical high-temperature neutron source under study. Initial analyses based upon published literature data and established fracture mechanics models indicate that the service life of such a system would be limited by fatigue, and that viability would require designers to limit the magnitude of the alternating stress, keeping it well below 10 MPa in order to achieve a service life of 1 year with an assumed availability of 85 percent. These standard analyses use analytical expressions from published sources such as Roark's Handbook. The applied static stress is either assumed, or taken from parallel predictions made with finite element model (FEM) codes. The alternating stress is predicted with formulae that account for (1) thermal stress pulses associated with isochoric heating of the structural material; and (2) pressure pulses from any working fluid in contact with the vessel wall. With published mechanical property data for the irradiated structural material, including the yield strength ( YS ) and fracture toughness (K C ), the critical flaw size for initiation of a fatigue crack (a c ) can then be estimated. The calculated critical flaw size (a c ), and the largest expected manufacturing defect in the surface (a 0 ) are required to calculate the number fatigue cycles to failure (N f ) as a function of applied stress (). The fatigue limit ( CR ) can be estimated once the required number of fatigue cycles are specified, which in this case are in excess of 200 million (268,056,000) cycles. Given the fatigue limit and the yield stress, the Soderberg equation is used to establish the most conservative bounds for the mean and alternating stresses, levels that cannot be exceeded for safe operation. Less conservatively, and given the fatigue limit and ultimate tensile strength of the material, the Goodman equation can be used to establish these bounds. Even more optimistic estimates can be made with the Gerber equation. Of course, more complicated alternating stress waveforms can be accounted for using the damage accumulation model, with cycle counting based upon the rainfall criterion. Model parameters were based experimental data for FM steels from a number of published sources, and recently published data on the mechanical testing of EUROFER97 and EUROFER97 HT after irradiation to 71 dpa in the BOR-60 reactor in Russia. These data indicate that radiation-induced damage, strengthening and hardening, and ductile brittle transition temperature (DBTT) increases approach saturation levels after a damage level of 10 to 20 displacements per atom (dpa) is reached.

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Microstructure of High‐Chromium Ferritic–Martensitic Steels for Next‐Generation Reactors

Košovský,

Dekan,

Sedlačková

et al. 2023

Physica Status Solidi (b)

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High‐chromium steels are key alloys used for the construction of technological devices in industry. Stainless steels are suitable for components that are exposed to a corrosive environment for a long time because chromium has anticorrosion properties due to segregation of chromium and the formation of a passivation layer. The physicochemical properties of the surface and the bulk of the material as well are determined by microstructure. Herein, steel NS219 is focused on, where the chromium concentration is around 13.5 wt%. In order to study the microstructure of steel, Mössbauer spectroscopy is used. Experimental results are evaluated using the binomial distribution model of the probability distribution of atoms in the nearest neighbor of the resonant atom 57Fe. Obtained spectral parameters, viz., the average magnetic hyperfine field, the average isomer shift, and the probability of the atomic configuration with no impurity atoms in the two‐shell vicinity of the iron atoms, reach saturation values from which the solubility limit of chromium in iron can be determined. On the other hand, the solubility limit of iron in Cr‐rich phase can be estimated from the value of the isomer shift of the single‐line in the spectrum annealed for the longest time.

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Mechanical properties and TEM examination of RAFM steels irradiated up to 70dpa in BOR-60

Cited by 104 publications

References 14 publications

Evolution of microstructure in advanced ferritic-martensitic steels under irradiation: the origin of low temperature radiation embrittlement

Evolution of microstructure in advanced ferritic-martensitic steels under irradiation: the origin of low temperature radiation embrittlement

Fatigue Life Prediction for Steels in Pulsating Irradiated Systems

Microstructure of High‐Chromium Ferritic–Martensitic Steels for Next‐Generation Reactors

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