Central Research Institute of Structural Materials Prometey

Saint Petersburg, Russia

Central Research Institute of Structural Materials Prometey

Saint Petersburg, Russia
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Kondrat'ev S.Y.,Polytechnic University of Mozambique | Sviatysheva E.V.,Central Research Institute of Structural Materials Prometey | Anastasiadi G.P.,Polytechnic University of Mozambique | Petrov S.N.,Central Research Institute of Structural Materials Prometey
Acta Materialia | Year: 2017

The structure of niobium carbide particles in as-cast heat resistant modified HP40NbTi alloy have been studied by light and electron microscopy, electron microprobe and X-ray diffraction. The niobium carbide particles in the structure of the HP40NbTi alloys are a multiphase polycrystal clusters with inhomogeneous chemical composition and crystallographic form. The boundaries between the crystals of the carbide particle are large-angle; the disorientation angle between crystals is 30–60°. Polycrystalline character of carbides is, probably, connected with the high thermal stress arising at interphase boundaries in the alloy structure at primary cooling of an ingot. The explanation of the polymorphic character of a niobium carbide cluster requires an independent analysis on the basis of a structural and geometrical crystallography. © 2017 Acta Materialia Inc.


Rybin V.V.,Saint Petersburg State University | Zolotorevskii N.Y.,Saint Petersburg State University | Ushanova E.A.,Central Research Institute of Structural Materials Prometey
Technical Physics | Year: 2014

The existing concepts of the mechanisms of forming fragmented structures under the conditions of severe plastic deformation of crystalline solids are analytically reviewed. The translational and rotational plasticity modes that develop at micro- and mesoscopic structural levels, respectively, are sequentially taken into account. This allows us to correctly describe the morphological features of the evolution of fragmented structures, to predict misorientation spectra for various fragmentation mechanisms, and to determine the partial contribution of each mechanism in the cases where several deformation grain refinement mechanisms are involved in fragmentation. The computer simulation of deformation-induced misorientation spectra that was developed using these concepts is a new method for studying the physical nature of structure formation processes, and this method can be applied for various materials, temperature-rate deformation conditions, and technological loading schemes. As an example, we comprehensively consider the formation of fragmented structures under the extreme conditions of explosion welding of commercial-purity copper plates. A comparison of the model misorientation spectra calculated for a reference structure and the fragmented structure in the near-contact zone of the welded joint with the existing experimental data demonstrates the efficiency and reliability of the proposed method. © 2014, Pleiades Publishing, Ltd.


Margolin B.,Central Research Institute of Structural Materials Prometey | Shvetsova V.,Central Research Institute of Structural Materials Prometey | Gulenko A.,Central Research Institute of Structural Materials Prometey
International Journal of Fracture | Year: 2013

The purpose of the present article is to develop a multi-scale brittle fracture modelling for irradiated RPV materials. For this development, applicability of local brittle fracture criteria for radiation embrittlement modelling is analysed through comparison of the predicted and test results on radiation embrittlement of RPV steels in terms of ductile-to-brittle transition temperature and fracture toughness. The influence of radiation-induced defects on the processes of cleavage microcrack nucleation and propagation is clarified. The physical-and-mechanical models of the effect of irradiation-induced defects on cleavage microcrack nucleation are developed on the basis of dislocation and brittle fracture theories. Stress-and-strain controlled fracture criterion is developed that allows the adequate prediction of radiation embrittlement by various mechanisms. The differences and commonalities are revealed in the nature of material embrittlement due to cold work and neutron irradiation. The mechanism is explained of significant recovery of fracture resistance properties with simultaneous increase of fraction of intercrystalline fracture after post-irradiation annealing. Engineering approach for prediction of the temperature dependence of fracture toughness as a function of neutron fluence is justified. © 2012 Springer Science+Business Media Dordrecht.


Margolin B.Z.,Central Research Institute of Structural Materials Prometey | Yurchenko E.V.,Central Research Institute of Structural Materials Prometey | Morozov A.M.,Central Research Institute of Structural Materials Prometey | Chistyakov D.A.,Central Research Institute of Structural Materials Prometey
Journal of Nuclear Materials | Year: 2014

A new method has been proposed for prediction of the effects of thermal ageing on the embrittlement of reactor pressure vessel (RPV) steels. The method is based on the test results for materials in two conditions, namely, aged at temperatures of temper embrittlement and annealed after irradiation. The prediction is based on the McLean's equation and the dependencies describing thermally activated and radiation-enhanced phosphorus diffusion. Experimental studies have been carried out for estimation of thermal ageing of the WWER-1000 RPV 2Cr-Ni-Mo-V steel. The ductile to brittle transition temperature shift ΔTk due to phosphorus segregation has been estimated on the basis of experimental data processed by the proposed method for the time t = 5 × 105 h (more than 60 years of operation) for the base and weld metals of the WWER-1000 RPV. © 2014 Elsevier B.V. All rights reserved.


Sorokin A.A.,Central Research Institute of Structural Materials prometey | Margolin B.Z.,Central Research Institute of Structural Materials prometey | Kursevich I.P.,Central Research Institute of Structural Materials prometey | Minkin A.J.,Central Research Institute of Structural Materials prometey | Neustroev V.S.,Research Institute of Atomic Reactors
Journal of Nuclear Materials | Year: 2014

Tensile properties of austenitic stainless steels used for pressure vessel internals of WWER type reactors (18Cr-10Ni-Ti steel and its weld metal) in the initial and irradiated conditions were investigated. Based on the presented original investigations and generalization of the available experimental data the dependences of yield strength and ultimate strength on a neutron damage dose up to 108 dpa, irradiation temperature range 320-450 C and test temperature range 20-450 C were obtained. The method of determination of the stress-strain curve parameters was proposed which does not require uniform elongation of a specimen as an input parameter. The dependences was proposed allowing one to calculate the stress-strain curve parameters for 18Cr-10Ni-Ti steel and its weld metal for different test temperatures, different irradiation temperatures and doses. The dependences were obtained to describe the fracture strain decrease under irradiation at a temperature range 320-340 C when irradiation swelling is absent. © 2013 Published by Elsevier B.V.


Margolin B.,Central Research Institute of Structural Materials Prometey | Sorokin A.,Central Research Institute of Structural Materials Prometey
Journal of Nuclear Materials | Year: 2014

A drastic decrease in the ultimate tensile strength of irradiated austenitic steels with high swelling values is considered. The physical-mechanical model proposed in Part 1 of the present paper is applied for the prediction of a drastic decrease in ultimate tensile strength. The mechanism called by the authors the "running collapse mechanism" is used for modeling the material ductile fracture when stresses are less than the yield strength. This ductile mechanism is similar to brittle fracture when crack propagates unstable manner. Running collapse mechanism occurs due to evolution of vacancy voids resulting in irradiation swelling. Nanoscale of vacancy voids (void sizes, distance between voids) results in the possibility of ductile fracture in very small zones whose size is considerably smaller than the grain size. © 2014 Elsevier B.V. All rights reserved.


Kondrat'ev S.Y.,Polytechnic University of Mozambique | Anastasiadi G.P.,Polytechnic University of Mozambique | Petrov S.N.,Central Research Institute of Structural Materials Prometey | Ptashnik A.V.,Central Research Institute of Structural Materials Prometey
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2016

The kinetics of formation and morphology of the intermetallic phases in the structure of heat-resistant as-cast HP40NbTi alloys in the course of long high-temperature exposure have been studied with the help of light and electron microscopy, electron microprobe, and X-ray diffraction. During exposure of 2 to 1000 hours at 1423 K (1150 °C), intermetallic phase with conditional formula Cr7Ni5Si3N3FeNb is formed in the alloy. The analysis of the kinetics of intermetallic phase’s growth for an impact assessment of certain metal substitutional elements (niobium, chromium, silicon) on the size of the formed particles was performed. Formation and growth of the intermetallic phases with high silicon content in the alloy structure on the boundaries between niobium and chromium carbides (NbC and M23C6) and matrix γ-phase provide a diffusion barrier for oxygen in oxidizing environment. This may create partial protection against oxidation of hardening carbide phases in the structure and promote increasing of the serviceability of the HP series alloys under operating conditions in the petrochemical industry. © 2016 The Minerals, Metals & Materials Society and ASM International


Vaynerman A.A.,Central Research Institute of Structural Materials Prometey | Vaynerman A.E.,Central Research Institute of Structural Materials Prometey
Tsvetnye Metally | Year: 2015

Nowadays, new austenite nitrogenous steel (Fe-Cr-Ni-Mn-N composition) is more applied to manufacturing of sea technical equipment structures, which obtaining requires copper alloy welding with this steel. Copper alloy welding with new austenite nitrogenous steel has the following peculiarities: eventual boiling of weld pool; nitrogen emission; formation of cracks in steel; partially contained copper alloy and formation nitrides in weld metal. Application of sublayer, cladded by EW-263ESR wire on this steel, together with scraping of base metal and acid-etching of filler metal, are necessary for receiving of qualitative welded joints of copper alloys with new austenite nitrogenous steel. Optimum conditions of TIG-welding deposition of sublayer, cladded by EW-263ESR wire on the steel was researched and installed together with amount of cladded layers of this sublayer metal, its optimum composition and metal structure, providing the absence of cracks and other defects, values of tensile strength and impact strength at steel level. There is shown the necessity of second sublayer, cladded by CuNiFeSiTi 5-1-0,2-0,2 wire on sublayer, cladded by EW-263ESR wire on Cr-Ni-Mn-N composition. On the basis of these researches, there was developed the process of TIG-welding of CuNiFe 5-1 grade alloy with new austenite nitrogenous steel composition thickness up to 15 mm grade, providing the quality of weld, tensile strength (CuNiFe 5-1 grade alloy) and high values of impact strength.


Margolin B.Z.,Central Research Institute of Structural Materials Prometey | Yurchenko E.V.,Central Research Institute of Structural Materials Prometey | Morozov A.M.,Central Research Institute of Structural Materials Prometey | Pirogova N.E.,Central Research Institute of Structural Materials Prometey | Brumovsky M.,Nuclear Research Institute Řež
Journal of Nuclear Materials | Year: 2013

The effect of neutron flux on embrittlement of WWER RPV materials is analyzed for cases when different radiation defects prevail. Data bases on the ductile-brittle transition temperature shifts obtained in the surveillance specimens programs and the research programs are used. The material embrittlement mechanisms for which the flux effect is practically absent and for which the flux effect is remarkable are determined. For case when the phosphorus segregation mechanism dominates the theoretical justification of the absence of the flux effect is performed on the basis of the theory of radiation-enhanced diffusion. © 2012 Elsevier B.V. All rights reserved.


Fedorova V.,Central Research Institute of Structural Materials Prometey | Margolin B.,Central Research Institute of Structural Materials Prometey
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2013

Austenitic stainless steels are used extensively as structural materials in the internal components of reactor pressure vessels. However, high neutron doses lead to a significant reduction in the fracture resistance of these steels in water environment. Irradiation assisted stress corrosion cracking (IASCC) of internals has been observed in pressurized water reactors (PWRs). In the present work the IASCC model of the irradiated austenitic steels in PWR water has been developed. On the basis of analysis of available experimental data IASCC mechanism is proposed. Based on this mechanism, the dependence of fracture stress under IASCC on neutron dose is derived. For its construction the following assumptions were made. 1. Creep rate due to grain boundary sliding does not depend on neutron dose. 2. Fracture strain due to grain boundary sliding decreases when neutron dose increases. 3. There is an apparent stress threshold below which IASCC initiation does not occur in PWR environment. Life prediction analysis for IASCC is performed on the basis of linear rule of damage accumulation. Copyright © 2013 by ASME.

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