Volume 8, Nº 6 (2017)

The procedure for calculating the J-integral for assessment of the lifetime of a reactor pressure vessel was developed according to the brittle fracture criterion under emergency core cooling conditions. An approach to the choice of the size of the integration contour was formulated for an adequate assessment of the brittle fracture resistance.

This article discusses the behavior of δ-ferrite upon crystallization, solidification, and subsequent cooling of solid nitrogen-containing stainless steel of various compositions on the basis of thermodynamic simulation. The results are confirmed experimentally and can be applied for selection of the steel composition as well as its production at all stages, including hot plastic working and welding, where δ-ferrite can be useful provided that its content is controlled. These results can be applied also for selection of temperature modes of austenitization aiming at the most complete dissolution of δ-ferrite in the final metal.

High-strength titanium pseudo-β-alloy (VT47) alloyed with rare earth metals intended for the geometrically complex plate structures of aircraft was developed. A combination of mechanical and technological properties for the VT47 alloy after its thermal treatment in different modes was shown. The further possible development of new materials with regulated β-structure was shown.

The microstructure and chemical composition of phases and inclusions in Ti–5Al–4V–2Zr alloys are studied in the initial state, after irradiation by titanium ions to radiation damage dose of ~1 dpa at 260°C, and after thermal aging at 450°C for 1000 h. Microstructural studies are carried out using scanning electron microscopy and atom probe tomography. Phase analysis is performed using energy dispersive X-ray spectroscopy. Chemical analysis of grains of the matrix phase and β-phase is presented. Spatial distribution of chemical elements in α- and β-phase lamellae is analyzed by atom probe tomography. Formation of nanosized vanadium pre-precipitates in the α-phase is observed in irradiated material.

Taken as a basis, BrAZhNMts 8-1.5-5-1.5 bronze powder was used to investigate the possibilities of applying functional-gradient coatings by gas-dynamic and microplasma spraying. It was experimentally established, that the oxide film on the surface of bronze particles hinders the formation of the coating by gasdynamic spraying. Two methods for the oxide film destruction were suggested: the first one was utilization of alumina in the spraying process, and the second one was manufacturing composite bronze-based powder in a vibrating mill. The influence of ceramic particles on the bronze coating hardness was investigated. The paper analyzes the prospects of using such coatings for the protection of important parts of marine equipment.

The paper presents the results of comparative tests for new heat-resistant electrical insulating polymer composite materials based on glass tissue and various polymeric binders and designed to operate at temperatures up to 280°C. Thermosetting (epoxy, organosilicon, and polycyanurate) and thermoplastic (polyphenylene sulfide) binders are investigated.

Results are presented for dilatometric and metallographic investigations and determination of microhardness for weld metal made of the materials for the automatic welding of VVER reactor vessels and oil hydrocracking reactor vessels. It is found that small differences in the content of alloying elements, such as nickel, chromium, molybdenum, and vanadium, cause differences in the structure of the weld metal before heat treatment.

The paper considers new generation platinum-niobium anodes developed on the basis of the 15-year experience of AKK-M-4 anodes operating as a part of a cathodic protection system for the nuclearpowered icebreaker 50 Let Pobedy, which can provide protection against erosion-corrosion damage of modern icebreakers and undocked ice-resistant offshore structures without repair and replacement for up to 25 years or more. Updated ice-resistant anodes such as AKL-2MU and AKL-3MU have been developed.

Before 2002, SE(B) specimens were included in surveillance specimen sets for operating VVER-1000 reactors. The transition from SE(B) specimens to CT specimens in the fracture toughness tests is caused by the necessity to reduce the scatter and the conservativeness of results caused by the scale increase and the loading scheme. To make such a transition possible, SE(B) specimens were reconstructed into CT specimens. The comparative fractographic analysis of standard and reconstructed CT specimens after the fracture toughness tests shows that the crack initiation in both types starts from the “origin.” The types of “origins” and their ratios do not change, and the test results and the fractographic analysis data for standard and reconstructed CT specimens are described by one analytical dependence CTOD(CID) for each material and state.

The radiation resistance of advanced Ti–5Al–4V–2Zr, Ti–5Al–2Mo–2Zr, and Ti–4Al–Mo–20Zr titanium alloys after neutron irradiation damaging dose of 0.29 dpa at irradiation temperature of 260°C was studied. The results of mechanical and microstructural tests of specimens carried out by transmission electron microscopy are presented; the distribution profiles of the alloying elements obtained by the energydispersive X-ray spectroscopy were studied.