Tilda Publishing

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Tilda Publishing

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

2024, No. 5, CONTENTS

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Tilda Publishing

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

2024, No. 5, ABSTRACTS

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Selective laser melting of plasma spheroidized tungsten powder
with a fine crystalline particle structure

M. Y. Gryaznov¹, A. V. Samokhin², V. N. Chuvildeev¹, A. A. Dorofeev²,
S. V. Shotin¹, A. A. Fadeev², N. V. Alekseev<sup>2

1</sup> National Research Lobachevsky State University of Nizhny Novgorod,
23 Gagarina ave., 603022 Nizhny Novgorod, Russia
E-mail: gryaznov@nifti.unn.ru; chuvildeev@nifti.unn.ru; shotin@nifti.unn.ru
² Baikov Institute of Metallurgy and Materials Science of the Russian Academy of Science (IMET RAS),
49 Leninsky prospect, 119334 Moscow, Russia

E-mail: asamokhin@imet.ac.ru; adorofeev@imet.ac.ru; afadeev@imet.ac.ru; nvalexeev@yandex.ru
The paper demonstrates for the first time the possibility of using an unalloyed tungsten powder with a spherical particle shape from 5 to 45 microns with a grain size of 0.5 – 2 microns obtained using plasma chemical synthesis, granulation and spheroidization technologies to create products using additive technologies. The influence of the technological parameters of the selective laser melting (SLM) process on the physico-mechanical characteristics and microstructure of test samples made of unalloyed tungsten powder has been studied. It is shown that the SLM parameters have a significant effect on the formation of the microstructure of test samples. It has been experimentally proved that at optimal parameters of the SLM process, a homogeneous equiaxed microstructure with an average grain size of about 10 microns is formed in the samples. It was found that the maximum value of the Vickers hardness of the studied SLM-samples of unalloyed tungsten is 310 HV10, the maximum value of microhardness is 4,1 GPa. The maximum density value of the obtained samples is 19,1 g/cm3 (relative density is 99,2 %). At the same time, it was found that a high crystallization rate and a large temperature gradient during the SLM process lead to the formation of microcracks and micropores in the structure of massive samples, which greatly complicates the technological task of obtaining high-density defect-free bulk products from unalloyed tungsten.

Keywords: unalloyed tungsten, spherical powder, additive technologies, selective laser melting, microstructure, hardness, density.

DOI: 10.30791/0015-3214-2024-5-5-20

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Electrodeposition of ZnNiCo coatings under the stimulating
action of X-ray radiation

N. G. Valko¹, V. М. Anishchik², E. Е. Kopishev³, D. V. Lavysh<sup>1

1</sup> Yanka Kupala State University of Grodno, 22 Ozheshko str., 230023 Grodno, Belarus
E-mail: N.Valko@grsu.by; demoniff@mail.ru
² Belarusian State University, 4 Nezavisimosti Avenue, 220030 Minsk, Belarus
E-mail: anishchik@mail.ru
³ L.N. Gumilyov Eurasian National University, 2 Satpayev str., 010008 Astana, Republic of Kazakhstan
E-mail: eldar_kopishev@mail.ru

The results of study of an electrodeposition kinetics, structure and properties of ZnNiCo coatings deposited onto low-carbon 08kp steel (St 50-2) under X-ray irradiation are presented. Deposition was performed with a preliminary reverse during 5 minutes, for 1 hour, in the X-ray field (Pexp = 100 kR/h), at 1 A/dm2, at controlled temperature of 23 °C. It was found that the X-ray irradiation of electrolytes during the deposition of ZnNiCo coatings causes a 10 % mass gain and a 30 % increase in the range of cathode current densities. It is shown that X-ray irradiation results to forming the coatings with a less developed surface morphology and a 30 % reduce in a roughness, which is associated with an increase in the dispersing ability of electrolytes due to stimulation of convective and diffusion transfer by effect of X-rays. It is established that exposure with X-rays of the electrolyte during the electrodeposition process leads to the formation of alloys with an increased content of the less electronegative component in comparison with control coatings. It was found that the effect of X-rays during the electrodeposition of ZnNiCo coatings leads to the formation of coatings with a 23 % increase in dislocation density, a 25 % increase in microhardness and a 50 % improve in a adhesion, which is associated with activation of the cathode surface.

Keywords: X-rays, electrodeposition, ZnNiCo coatings, kinetics, structure, properties.

DOI: 10.30791/0015-3214-2024-5-21-27

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Kinetics of mass transfer during the formation of diffusion
cobalt coatings from liquid metal solutions

E. G. Sokolov, A. V. Ozolin, E. E. Bobylev, D. A. Golius

Kuban State Technological University (KubSTU),
2 Moskovskaya str., 350072 Krasnodar, Russia
E-mail: e_sokolov.07@mail.ru

The paper shows the possibility of forming diffusive cobalt and cobalt-tungsten coatings on Armco-iron from lead-based liquid metal solutions. In the temperature range 900 – 1050 °C, cobalt coatings with a surface content of 15 – 23 wt. % cobalt were obtained on iron. The introduction of a liquid metal solution of finely dispersed tungsten powder affects the mass transfer of cobalt and makes it possible to obtain cobalt-tungsten diffusion coatings on iron with a surface content of up to 11 wt. % cobalt and up to 24 wt. % tungsten.

Keywords: diffusion coating, liquid metal solution, isothermal mass transfer, cobalt, tungsten.

DOI: 10.30791/0015-3214-2024-5-28-36

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Study of powder prepared by milling waste sintered NdFeB permanent magnets

I. V. Belyaev¹, N. B. Kolchugina², V. Е. Bazhenov³, P. S. Mogil’nikov3, M. V. Zheleznyi^2, 3,
N. P. Edunov¹, P. A. Prokofev², R. A. Vakhrushev<sup>2, 3

1</sup> Vladimir State University named after Alexander and Nikolay Stoletovs (VLSU),
87 Gorky str., 600037 Vladimir, Russia
E-mail: belyaev-iv54@yandex.ru
² Baikov Institute of Metallurgy and Materials Science of the Russian Academy of Science (IMET RAS),
49 Leninsky prospect, 119334 Moscow, Russia

E-mail: nkolchugina@imet.ac.ru; markiron@mail.ru; pav3387@yandex.ru; vakhrushev.r.a@yandex.ru
3 National University of Science and Technology MISIS, 4 Leninsky prospect, 119049 Moscow, Russia
At the end of lifetime of various facilities, a great amount of worked-out permanent magnets forms, which no longer in practice and are industrial wastes. The reuse of these wastes in manufacturing NdFeB sintered permanent magnets (so-called recycling) would substantially decrease the cost of the magnets, which are usually prepared from not only expensive but also deficient initial components. The modern research methods, such as the electron microscopy, X-ray fluorescence, gas, and X-ray diffraction analysis and magnetometry are used to study the chemical and phase compositions and magnetic properties of powder prepared by crushing and subsequent milling in an isopropyl medium of waste NdFeB sintered magnets. The used crushing and milling processes are one of processes comprising the manufacturing procedure of sintered permanent NdFeB magnets by powder metallurgy and should not change the phase composition of the alloy. The maximum powder particle size obtained after milling the waste sintered permanent magnets was 50 µm. The prepared powder was found to be characterized by the increased oxygen content. The phase composition (wt. %) comprises 82.0 % Nd2Fe14B, 9.7 % Nd(OH)3, 8.0 % α-Fe, and 0.3 % Nd2O3. The oxide phases are present at the powder particle surface. The powder material is shown to be characterized by sufficiently high level of magnetic properties. The possibility of application of the powder in manufacturing sintered permanent magnets, in particular, by 3D printing technology is discussed.

Keywords: waste magnets, milling, powder material, phase composition, magnetic properties of NdFeB.

DOI: 10.30791/0015-3214-2024-5-37-43

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Influence of particle sizes of aluminum oxide powder on ceramic sintering in a constant magnetic field

A. P. Klishin¹, S. A. Ghyngazov², V. I. Vereshchagin<sup>2

1</sup> Tomsk State Pedagogical University, 60 Kiyevskaya str., 634061 Tomsk, Russia
E-mail: klishin@tspu.edu.ru
² National Research Tomsk Polytechnic University, 30 Lenina str., 634050 Tomsk, Russia
E-mail: ghyngazov@tpu.ru; vver@tpu.ru

The properties of ceramics obtained by sintering compacts from powders of ultradispersed and microdispersed aluminum oxide in a constant magnetic field have been studied. Activation sintering of aluminum oxide in a constant magnetic field makes it possible to reduce the sintering temperature of ceramics while improving its quality. It has been established that the influence of the magnetic field is the most strongly appeared during sintering of compacts from micropowders. Their characteristics such as density, microhardness, and ultimate strength significantly exceed the corresponding values determined for ceramics obtained by sintering compacts of ultrafine alumina in a magnetic field.

Keywords: aluminum oxide, sintering, constant magnetic field, ultrafine powders.

DOI: 10.30791/0015-3214-2024-5-44-53

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Changes in the microstructure and mechanical properties of Zr – 1 % Nb (E110) alloy cladding during thermal tests of VVER-1000 fuel elements simulating dry storage conditions

G. P. Kobylyansky, I. N. Volkova, E. A. Zvir, P. A. Ilyin, A. V. Obukhov,
D. E. Markelov, E. V. Chertopyatov, A. O. Mazaev

JSC “SSC RIAR”, 9 Zapadnoye Shosse, 433510 Dimitrovgrad, Russia
E-mail: gpk@niiar.ru; ea-zvir@niiar.ru

Thermal tests of two types were performed in helium to simulate dry storage conditions for fuel rods with claddings made of Zr – 1 % Nb (E110) alloy which had been operated in the VVER-1000 reactors up to the average calculated fuel burnup values of 20, 63 and 70 MWD/kgU. The first type of tests was performed under two conditions: steady-state (holding at T = 380 °C for 468 days) and thermal cycling (48 thermal cycles at 90 °С/380 °С with the different duration of cycles from 1 to 10 days and total time of testing was 427 days). The second type of tests had two stages. At the first stage two modes were achieved: vacuum drying (step-by-step heating and holding at each stage for a day at temperatures of 200 °C, 400 °C and 440 °C) and vacuum drying together with a simulated design basis accident (there was a step-by-step temperature reduction from 440 °С to 380 °С and to 360 °С after vacuum drying and the time of holding was 14 and 168 hours, respectively). Fuel rods were held at T = 350 °С for 404 days at the second stage. The thermal impact caused a decrease in the density of radiation-induced <a>-type dislocations, the ratio of Nb atoms in β-Nb particles, and the size of the particles. Radiation-induced defects in the structure annealed more severely as a result of thermal tests of the first type as compared to the second type. Partial annealing of the radiation-induced defects led to a partial regain of the yield strength of the claddings to the original values to a greater extent in the longitudinal direction rather than in the transverse one. The better recovery of yield strength as a result of thermal tests of the first type rather than of the second type is due to the higher efficiency of temperature impact as a function of time on the microstructure of the E110 alloy that is estimated as the relevant cumulative annealing parameter. Different conditions of each thermal test did not lead to a significant difference in the yield strength recovery. Tensile stresses occurred in the claddings at high temperatures during thermal tests of both types contributed to the reorientation of zirconium hydrides as the radial orientation factor Fn increased up to 0.3 with a minor decrease in their specific length. It did not cause a reduction in the plasticity of the claddings due to the low hydrogenation degree.

Keywords: fuel element cladding, alloy E110, VVER-1000, thermal test modes, morphology of zirconium hydrides, radiation damage to the structure, strength, ductility.

DOI: 10.30791/0015-3214-2024-5-54-69

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Microstructure of the contact zone during high-temperature interaction of carbon fiber and Fe – Al melt

А. Е. Sytschev, О. D. Boyarchenko, S. G. Vadchenko, М. L. Busurina

Merzhanov Institute of Structural Macrokinetics and Materials Science of the Russian Academy of Sciences (ISMAN RAS),
8 Academician Osipyan str., 142432 Chernogolovka, Russia
E-mail: sytschev@ism.ac.ru

The work has been studied peculiarities of the microstructure formation in the Fe – Al – C system during high-temperature interaction of the Fe – Al melt with the carbon fibers. The results of microstructural studies have shown that the spherical droplets of ~ 300 µm in average size are formed on the surface of carbon fibers. According to the X-ray phase and microstructural cross-section analysis, the composition of the droplets basically corresponds to a composite structure based on the cubic carbide phase of iron aluminide Fe3AlCx in a Fe3Al-based matrix. Fe3AlCx phase has been formed as a result of a highly exothermic reaction between graphite and the Fe – Al melt. Microstructure investigation of droplets fracture surface has revealed that a distinct cellular structure with a cell size of ~ 200 nm is formed inside the grains of iron aluminide due to a concentration undercooling, caused by the nonequilibrium of the synthesis process. As a result of the segregation of carbon atoms dissolved in a molten drop of Fe – Al melt, a multilayer graphite coating with a thickness of about 5 µm is formed on the surface of the Fe – Al drops. The heterogeneity of the chemical composition of dendritic crystallites has been determined from the results of energy-dispersive analysis and is probably caused by the dendritic liquation. The average microhardness of the spherical droplet material was ~ 2500 MPa, the maximum microhardness value reached 4580 MPa. The results of the work can be used in the production of composite materials based on iron aluminides reinforced with carbon fibers coated with double iron carbide Fe3AlCx.

Keywords: intermetallics, Fe – Al – C, carbon fibers, graphite coating.

DOI: 10.30791/0015-3214-2024-5-70-78

ПЕРСПЕКТИВНЫЕ МАТЕРИАЛЫ

Influence of partitioning process during Q&P heat treatment on the microstructure
and properties of medium carbon cast steel ZG30MnSiMo (1.5 % Mn – 1.5 % Si)

Zhang Yong-Jun, Liu Sen, Han Jing-Tao

School of Materials Science and Engineering, University of Science and Technology Beijing,
30 Xueyuan Road, Haidian District, 100083 Beijing, China
E-mail: zhangyj@mater.ustb.edu.cn

The microstructure and properties of medium carbon cast steel ZG30MnSiMo(1.5 % Mn – 1.5 % Si) subjected to heat treatment of quenching and partitioning (Q&P) are investigated. The results show that the microstructure of cast steel after this heat treatment mainly consists of lath martensite and residual austenite. With the increase in temperature or in the time of partitioning, granular carbides appear inside martensitic matrix, the volume fraction of residual austenite gradually increases, and the tensile strength gradually decrease, the elongation gradually and impact toughness increases. The parameter for effectively controlling PSE (Product of Strength and Elongation) is the temperature of partitioning. Compared to quenching low-temperature tempering treatment, the tested cast steel treated with quenching and partitioning has a higher hardening index, which shows that quenching and partitioning treatment helps to improve the wear resistance of cast steel.

Keyword: medium carbon cast steel, Quenching and Partitioning, microstructure, properties.

DOI: 10.30791/0015-3214-2024-5-79-86