Data are given on Zr alloy E635 (Zr-l.2Sn-lNb-0.4Fe), developed in Russia as a fuel rod cladding and other component material for use in cores of VVER and RBMK types. The alloy is much superior to binary alloys with 1.0 and 2.5% Nb and Zircaloys in terms of its resistance to irradiation-induced creep and growth and nodular corrosion. The creep rate of the alloy is slightly dependent on irradiation temperature, stress, neutron fluence, and neutron density. The alloy is subject to substantial irradiation hardening while retaining its high-percent elongation. Corrosion, creep, and growth resistances are slightly dependent on the structure of components (alloy, final product). Based on the previously studied influence of impurities, structure, heat treatment, and working schedules, the technological processes were designed and mastered commercially for fabrication of tubes, bars, strips, and fuel rod claddings from this alloy. Components are produced commercially. Fuel assemblies with fuel rods clad in the E635 alloy were successfully tested in the RBMK reactor at the Leningrad NPP as well as in experimental reactors under VVER-1000 conditions. Today, the E635 alloy is recommended as a promising material for use in cores of VVER-1000 and VVER of new generations as well as RBMK-type reactors having a longer fuel cycle.
The E110 alloy (Zr-1Nb) designed in Russia has been in successful operation in the VVER and RBMK reactors since 1960. The evolution of the Russian reactors during this period of time, their numbers and operating parameters, and, hence, the relevant production of the cladding tubes required much effort from the researchers and producers to optimize the technological processes resulting in the high operating reliability of the fuel rods clad in the E110 alloy. In the Zr-Nb system to which the E110 alloy pertains, highly sophisticated structure-phase transformations proceed depending on the temperature-rate conditions of processing and the impurity content of the alloy. The alloy structure formed during its processing affects substantially the processability and performance of semi-products and finished tubes. The paper demonstrates the interrelation between the structure-phase transformations of the E110 alloy and the temperature-rate conditions of processing as well as the oxygen content of the alloy. The phase composition and microstructure are shown to play an essential part in providing the tubes with the requisite properties and their stability. The properties of cladding tubes having different structures and fuel rod claddings as in-pile irradiated are analyzed. The corrosion behavior of E110 alloy claddings is shown to be strongly dependent upon the material structure and reactor operating conditions.
In order to ensure high wear resistance of parts and tools, operating at significant dynamic loads in the extreme conditions, the layers different in their function purpose obtained using surfacing methods are widely used. In such surfacing compositions, the powders of high-melting compounds characterized by high hardness and strength, are used as a wear resistant component, for example, alloys of tungsten carbide WC + W2C (cast tungsten carbide), and as binder matrix the plastic and metal alloys are used.The great interest is the development of methods allowing producing powders of cast tungsten carbide and other high-melting-point materials of uniform composition, characterized by a high sphericity of the particles and having higher physical-mechanical properties. The spherical tungsten carbide was produced by plasma atomization of rotating billet. The universal installation for production of super-hard spherical tungsten carbide and other high-melting-point compounds by plasma atomization of rotating billets was designed for industrial application. The results showed that the application of the technology of plasma rotary atomization of rotation billet to obtain granules of powders of high-melting-point materials was promising, in particular tungsten carbide with sphericity over 90%, microhardness HV0.1 more than 3000 kg / mm2 characterized by high flow ability more than 7.5 s/ 50 g. Due to the use of new materials and innovative design and technological solutions the high reliability, maximum interval of technical service, high resource of operating units and executing mechanism of the equipment were ensured. Due to the use of new high-power plasma system with power supply source with high efficiency coefficient and improved dynamic characteristics, the system of preliminary heating of billets, innovative gas systems, high performance vacuum system, the developed universal system for the production of granules of powders of high-melting-point material were also applicable for the manufacture of spherical powders of metals and alloys, including highly active, and provided lower costs of products (powder) with an increased productivity, economic efficiency of the atomization process and reduced the impact of atomization process on the environment.
Проведены комплексные исследовательские работы по получению способом электронно-лучевой плавки слитков жаропрочного сплава титана системы Ti-Si-Al-Zr-Sn, подвергнутых горячей пластической деформации для получения прутков-полуфабрикатов. Усовершенствована схема шихтовки и определены технологические параметры электронно-лучевой плавки слитков в модернизированной электронно-лучевой установке УЭ-208М. Исследованы химический состав и структура полученных слитков титановых сплавов системы Ti-Si-Al-Zr-Sn и показано, что материал характеризуется достаточно высокой химической однородностью. Проведена горячая деформационная обработка слитков электронно-лучевой плавки и получены качественные прутки-полуфабрикаты жаропрочного сплава системы Ti-Si-Al-Zr-Sn. Библиогр. 11, табл. 1, рис. 4.
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