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St.Petersburg, Russia

Nesterova E.V.,CRISM Prometey | Bouvier S.,CNRS Roberval Laboratory (Mechanical Research Unit) | Bacroix B.,University of Paris 13
Materials Characterization | Year: 2015

Transmission electron microscopy (TEM) microstructures of a high-strength dual-phase steel DP800 have been examined after moderate plastic deformations in simple shear and uniaxial tension. Special attention has been paid to the effect of the intergranular hard phase (martensite) on the microstructure evolution in the near-grain boundary regions. Quantitative parameters of dislocation patterning have been determined and compared with the similar characteristics of previously examined single-phase steels. The dislocation patterning in the interiors of the ferrite grains in DP800 steel is found to be similar to that already observed in the single-phase IF (Interstitial Free) steel whereas the martensite-affected zones present a delay in patterning and display very high gradients of continuous (gradual) disorientations associated with local internal stresses. The above stresses are shown to control the work-hardening of dual-phase materials at moderate strains for monotonic loading and are assumed to influence their microstructure evolution and mechanical behavior under strain-path changes. © 2014 Elsevier Inc. All rights reserved. Source

Rybin V.V.,CRISM Prometey | Greenberg B.A.,RAS Institute of Metal Physics | Ivanov M.A.,Ukrainian Academy of Sciences | Patselov A.M.,RAS Institute of Metal Physics | And 4 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2011

The microstructure of a bimetallic joint made by explosion welding of orthorhombic titanium aluminide (Ti-30Al-16Nb-1Zr-1Mo) with commercially pure titanium is studied. It is found that the welded joint has a multilayered structure including a severely deformed zone observed in both materials, a recrystallized zone of titanium, and a transition zone near the interface. Typical elements of the transition zone-a wavy interface, macrorotations of the lattice, vortices and tracks of fragments of the initial materials-are determined. It is shown that the observed vortices are formed most probably due to local melting of the material near the contact surface. Evidence for this assumption is deduced from the presence of dipoles, which consist of two vortices of different helicity and an ultrafine duplex structure of the vortex. Also, high mixing of the material near the vortex is only possible by the turbulent transport whose coefficient is several orders of magnitude larger than the coefficient of atomic diffusion in liquids. The role played by fragmentation in both the formation of lattice macrorotations and the passage of coarse particles of one material through the bulk of the other is determined. Copyright © 2011 American Scientific Publishers. All rights reserved. Source

Gorynin I.,CRISM Prometey | Timofeev B.,CRISM Prometey | Bazaras Z.,Kaunas University of Technology
Intelligent Technologies in Logistics and Mechatronics Systems, ITELMS 2011 - Proceedings of the 6th International Conference | Year: 2011

The generalized data on influence of operational temperatures 250-350°C on mechanical properties of the materials used for manufacturing of the main equipment (RPV, SG) and pipelines of the Russian NPP with LWR (WWER and RBMK reactors) for a prolonged operation time (100000 hours) are submitted. Degradation of mechanical properties of structural steels from this factor during designed service life is appreciated, and also the forecast of an opportunity of use of these materials at prolongation of service life. Source

Engelko V.,D.V. Efremov Scientific Research Institute of Eelectrophysical Apparatus | Mueller G.,Karlsruhe Institute of Technology | Rusanov A.,RAS Institute of Physics and Power Engineering | Markov V.,CRISM Prometey | And 5 more authors.
Journal of Nuclear Materials | Year: 2011

The alloying of steel surface with aluminum (Al) using Microsecond-pulsed Intense Electron Beams (MIEB-Al) was developed and optimized in order to be used for improving the corrosion resistance of the 316, 1.4970 and T91 steels, exposed to liquid Pb and Pb-Bi-eutectic. The procedure consists in two steps: (i) coating the steel surface with Al or an Al-containing alloy layer and (ii) melting the coating layer and the steel surface layer using intense pulsed electron beam. In order to cover the steel surface with an homogeneous and crack-free Al-alloyed layer, the following experimental conditions are required: Al coating thickness range 5-10 μm, electron kinetic energy 120 keV; pulse duration 30 μs; energy density 40-45 J/cm2; number of pulses 2-3. Using the mentioned procedure, the corrosion resistance of the 316, T91 and 1.4970 steels, exposed to Pb and Pb-Bi-eutectic with different oxygen concentrations and under different temperatures, was considerably improved due to the formation of a thin alumina layer (which thickness is lower than 1 μm for all the tested temperatures and durations) acting as an anti-corrosion barrier. © 2011 Published by Elsevier B.V. Source

Gurovich B.A.,RAS Research Center Kurchatov Institute | Kuleshova E.A.,RAS Research Center Kurchatov Institute | Frolov A.S.,RAS Research Center Kurchatov Institute | Maltsev D.A.,RAS Research Center Kurchatov Institute | And 4 more authors.
Journal of Nuclear Materials | Year: 2015

Abstract A complex study of structural state and properties of 18Cr-10Ni-Ti austenitic stainless steel after irradiation in BOR-60 fast research reactor (in the temperature range 330-400 C up to damaging doses of 145 dpa) and in VVER-1000 light water reactor (at temperature ∼320 C and damaging doses ∼12-14 dpa) was performed. The possibility of recovery of structural-phase state and mechanical properties to the level almost corresponding to the initial state by the recovery annealing was studied. The principal possibility of the recovery annealing of pressurized water reactor internals that ensures almost complete recovery of its mechanical properties and microstructure was shown. The optimal mode of recovery annealing was established: 1000 °C during 120 h. © 2015 Elsevier B.V. Source

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