Vol. 26 No. 4 2024 3 EDITORIAL COUNCIL EDITORIAL BOARD EDITOR-IN-CHIEF: Anatoliy A. Bataev, D.Sc. (Engineering), Professor, Rector, Novosibirsk State Technical University, Novosibirsk, Russian Federation DEPUTIES EDITOR-IN-CHIEF: Vladimir V. Ivancivsky, D.Sc. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Vadim Y. Skeeba, Ph.D. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Editor of the English translation: Elena A. Lozhkina, Ph.D. (Engineering), Department of Material Science in Mechanical Engineering, Novosibirsk State Technical University, Novosibirsk, Russian Federation The journal is issued since 1999 Publication frequency – 4 numbers a year Data on the journal are published in «Ulrich's Periodical Directory» Journal “Obrabotka Metallov” (“Metal Working and Material Science”) has been Indexed in Clarivate Analytics Services. Novosibirsk State Technical University, Prospekt K. Marksa, 20, Novosibirsk, 630073, Russia Tel.: +7 (383) 346-17-75 http://journals.nstu.ru/obrabotka_metallov E-mail: metal_working@mail.ru; metal_working@corp.nstu.ru Journal “Obrabotka Metallov – Metal Working and Material Science” is indexed in the world's largest abstracting bibliographic and scientometric databases Web of Science and Scopus. Journal “Obrabotka Metallov” (“Metal Working & Material Science”) has entered into an electronic licensing relationship with EBSCO Publishing, the world's leading aggregator of full text journals, magazines and eBooks. The full text of JOURNAL can be found in the EBSCOhost™ databases.
OBRABOTKAMETALLOV Vol. 26 No. 4 2024 4 EDITORIAL COUNCIL EDITORIAL COUNCIL CHAIRMAN: Nikolai V. Pustovoy, D.Sc. (Engineering), Professor, President, Novosibirsk State Technical University, Novosibirsk, Russian Federation MEMBERS: The Federative Republic of Brazil: Alberto Moreira Jorge Junior, Dr.-Ing., Full Professor; Federal University of São Carlos, São Carlos The Federal Republic of Germany: Moniko Greif, Dr.-Ing., Professor, Hochschule RheinMain University of Applied Sciences, Russelsheim Florian Nürnberger, Dr.-Ing., Chief Engineer and Head of the Department “Technology of Materials”, Leibniz Universität Hannover, Garbsen; Thomas Hassel, Dr.-Ing., Head of Underwater Technology Center Hanover, Leibniz Universität Hannover, Garbsen The Spain: Andrey L. Chuvilin, Ph.D. (Physics and Mathematics), Ikerbasque Research Professor, Head of Electron Microscopy Laboratory “CIC nanoGUNE”, San Sebastian The Republic of Belarus: Fyodor I. Panteleenko, D.Sc. (Engineering), Professor, First Vice-Rector, Corresponding Member of National Academy of Sciences of Belarus, Belarusian National Technical University, Minsk The Ukraine: Sergiy V. Kovalevskyy, D.Sc. (Engineering), Professor, Vice Rector for Research and Academic Aff airs, Donbass State Engineering Academy, Kramatorsk The Russian Federation: Vladimir G. Atapin, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Victor P. Balkov, Deputy general director, Research and Development Tooling Institute “VNIIINSTRUMENT”, Moscow; Vladimir A. Bataev, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Vladimir G. Burov, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Aleksandr N. Korotkov, D.Sc. (Engineering), Professor, Kuzbass State Technical University, Kemerovo; Dmitry V. Lobanov, D.Sc. (Engineering), Associate Professor, I.N. Ulianov Chuvash State University, Cheboksary; Aleksey V. Makarov, D.Sc. (Engineering), Corresponding Member of RAS, Head of division, Head of laboratory (Laboratory of Mechanical Properties) M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences (Ural Branch), Yekaterinburg; Aleksandr G. Ovcharenko, D.Sc. (Engineering), Professor, Biysk Technological Institute, Biysk; Yuriy N. Saraev, D.Sc. (Engineering), Professor, V.P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of the RAS, Yakutsk; Alexander S. Yanyushkin, D.Sc. (Engineering), Professor, I.N. Ulianov Chuvash State University, Cheboksary
Vol. 26 No. 4 2024 5 CONTENTS OBRABOTKAMETALLOV TECHNOLOGY Manikanta J.E., Ambhore N., Shamkuwar S., Gurajala N.K., Dakarapu S.R. Investigation of vegetable-based hybrid nanofl uids on machining performance in MQL turning........................................................................................... 6 Dama Y.B., Jogi B.F., Pawade R., Kulkarni A.P. Impact of print orientation on wear behavior in FDM printed PLA Biomaterial: Study for hip-joint implant...................................................................................................................... 19 GrinenkoA.V., ChumaevskyA.V., Sidorov E.A., Utyaganova V.R.,AmirovA.I., Kolubaev E.A. Geometry distortion, edge oxidation, structural changes and cut surface morphology of 100mm thick sheet product made of aluminum, copper and titanium alloys during reverse polarity plasma cutting...................................................................................... 41 Somatkar A., Dwivedi R., Chinchanikar S. Comparative evaluation of roller burnishing of Al6061-T6 alloy under dry and nanofl uid minimum quantity lubrication conditions............................................................................................... 57 Karlina Yu.I., Konyukhov V.Yu., Oparina T.A. Assessment of the quality and mechanical properties of metal layers from low-carbon steel obtained by the WAAM method with the use of additional using additional mechanical and ultrasonic processing..................................................................................................................................................... 75 EQUIPMENT. INSTRUMENTS Yusubov N.D., Abbasova H.M. Systematics of multi-tool setup on lathe group machines............................................... 92 Toshov J.B., Fozilov D.M., Yelemessov K.K., Ruziev U.N., Abdullayev D.N., Baskanbayeva D.D., Bekirova L.R. Increasing the durability of drill bit teeth by changing its manufacturing technology......................................................... 112 Pospelov I.D. Investigation of the distribution of normal contact stresses in deformation zone during hot rolling of strips made of structural low-alloy steels to increase the resistance of working rolls..................................................... 125 Ablyaz T.R., Blokhin V.B., Shlykov E.S., Muratov K.R., Osinnikov I.V. Manufacturing of tool electrodes with optimized confi guration for copy-piercing electrical discharge machining by rapid prototyping method.......................... 138 MATERIAL SCIENCE Shubert A.V., Konovalov S.V., Panchenko I.A. A review of research on high-entropy alloys, its properties, methods of creation and application.................................................................................................................................................. 153 Syusyuka E.N., Amineva E.H., Kabirov Yu.V., Prutsakova N.V. Analysis of changes in the microstructure of compression rings of an auxiliary marine engine.......................................................................................................... 180 Dudareva A.A., Bushueva E.G., Tyurin A.G., Domarov E.V., Nasennik I.E., Shikalov V.S., Skorokhod K.A., Legkodymov A.A. The eff ect of hot plastic deformation on the structure and properties of surface-modifi ed layers after non-vacuum electron beam surfacing of a powder mixture of composition 10Cr-30B on steel 0.12 C-18 Cr-9 Ni-Ti............................................................................................................................................................................. 192 Boltrushevich A.E., Martyushev N.V., Kozlov V.N., Kuznetsova Yu.S. Structure of Inconel 625 alloy blanks obtained by electric arc surfacing and electron beam surfacing........................................................................................... 206 Sablina T.Y., Panchenko M.Yu., Zyatikov I.A., Puchikin A.V., Konovalov I.N., Panchenko Yu.N. Study of surface hydrophilicity of metallic materials modifi ed by ultraviolet laser radiation........................................................................ 218 EDITORIALMATERIALS 234 FOUNDERS MATERIALS 243 CONTENTS
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 A review of research on high-entropy alloys, its properties, methods of creation and application Anna Shubert a, *, Sergey Konovalov b, Irina Panchenko c Siberian State Industrial University, 42 Kirov st., Novokuznetsk, 654007, Russian Federation a https://orcid.org/0000-0001-7355-2955, shubert-anna@mail.ru; b https://orcid.org/0000-0003-4809-8660, konovalov@sibsiu.ru; c https://orcid.org/0000-0002-1631-9644, i.r.i.ss@yandex.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2024 vol. 26 no. 4 pp. 153–179 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2024-26.4-153-179 ART I CLE I NFO Article history: Received: 21 April 2024 Revised: 17 May 2024 Accepted: 17 September 2024 Available online: 15 December 2024 Keywords: High-entropy alloys Wear resistance Heat resistance Thermal stability Plasticity Alloying Funding This study is funded by a grant of the Russian Science Foundation, project 23-49-00015. https://rscf.ru/en/ project/23-49-00015/. ABSTRACT Introduction. The paper discusses the prospects for studying high-entropy alloys (HEA), metal materials with unique properties. The study of high-entropy alloys is an urgent area of research in connection with its properties, environmental sustainability, economic benefi ts and technological potential. HEA are of interest to researchers due to its stability, strength, corrosion resistance and other characteristics, which makes it promising for use in the aerospace industry, automotive, medicine and microelectronics. Thus, HEA research contributes to the development of new materials and technological progress, providing opportunities for creating innovative products and improving existing solutions. To eff ectively use the potential of high-entropy alloys, research is required in a number of areas. First, it is necessary to improve the production technology of such alloys and develop newmethods for obtaining HEA with improved characteristics and reduced cost. Secondly, it is necessary to establish the basic principles of operation of high-entropy alloys and to study the mechanisms infl uencing its properties. It is also necessary to develop new alloys with specifi ed properties and conduct experiments and computer simulations to optimize the characteristics of the alloys and determine the best compositions. The purpose of the work is to study developments in the fi eld of high-entropy alloys and conduct a comparative analysis of published studies on improving the properties of high-entropy alloys. The research method is a review and analysis based on developments mainly for 2020-2024, which were carried out by domestic and foreign scientists. The paper discusses the prospects for the study of highentropy alloys, materials with a wide range of applications in various industries. The paper presents the results of research, mainly for 2020-2024. The main properties of high-entropy alloys are described, such as high strength, corrosion resistance, fatigue properties, plasticity and deformability, thermal stability, electrical conductivity and magnetic properties, as well as the possibility of creating alloys with specifi ed characteristics. The most common methods of changing the properties of alloys have been identifi ed. The directions of further development of research in this area are considered. Results and discussion: a literature review shows that developments and research are carried out on all possible properties of HEA, but most of it is devoted to corrosion-resisting properties and thermal stability. Of the methods used in high-entropy alloys, the most common and universal can be considered the alloying of high-entropy alloys with other metals. Studies also confi rm that alloying metals are selected depending on its characteristic properties. The number of scientifi c works also confi rms the relevance of this topic and the need for its study. The authors noted that future studies on the fatigue properties of high-entropy alloys, as well as the properties of alloys under the infl uence of magnetic and electric fi elds are the most interesting. For citation: Shubert A.V., Konovalov S.V., Panchenko I.A. A review of research on high-entropy alloys, its properties, methods of creation and application. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2024, vol. 26, no. 4, pp. 153–179. DOI: 10.17212/1994-6309-2024-26.4-153-179. (In Russian). ______ * Corresponding author Shubert Anna V., Post-graduate Student Siberian State Industrial University, 42 Kirova st., 654007, Novokuznetsk, Russia Tel.: +7 913 437-89-70, e-mail: shubert-anna@mail.ru Introduction The study of high-entropy alloys (HEAs) began relatively recently, in the early 21st century. Its investigation is driven by interest in creating new materials with unusual properties and potential for various applications.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 HEAs were proposed and studied in the early 2000s by a group of scientists led by Professor J. W. Yeh from the National Tsing Hua University in Taiwan. They published their research fi ndings in journals in 2004 [1]. HEAs represent a class of materials where fi ve or more distinct elements are mixed in equal or nearequal proportions [2]. This allows for the formation of new types of crystal structures and phases, including unconventional crystalline structures, amorphous regions, and other forms of atomic organization, which may exhibit unique properties. Modern research shows that high-entropy alloys can form structures and phases that have not previously been discovered or well-studied, expanding traditional ideas about the capabilities of this class of materials. The fi rst HEAs were created by melting and mixing elements in appropriate proportions, followed by cooling the resulting melt to obtain an alloy. This process distinguishes these materials from traditional alloys, where typically one or two primary elements dominate. HEAs are characterized by high confi gurational entropy of atoms, resulting from the even distribution of fi ve or more distinct elements in its structure. Although it was once thought that the formation of a singlephase structure and equal presence of elements are mandatory conditions, the modern concept of highentropy alloys continues to evolve. The introduction of elements in equal proportions and the formation of a single-phase structure are no longer considered strict requirements, opening up new opportunities for further research in this fi eld. Alloys can exhibit remarkable mechanical properties, such as high strength, hardness, and wear resistance, making it useful for developing lightweight yet strong materials for aviation, automotive, and other industries. Some HEAs are resistant to aggressive environments, making it suitable for applications where materials need to retain its properties over extended periods. Due to its composite nature, HEAs can also be more accessible and cost-eff ective to produce compared to traditional alloys. Over the past few decades, interest in alloys developed based on the entropy approach has grown signifi cantly, driven by the potential of HEAs. Abroad, the idea of high-entropy alloys was proposed in the early 2000s. In Russia, research into high-entropy alloys began a little later. The fi rst publications and studies by Russian scientists in this fi eld appeared in the late 2000s and early 2010s. By 2010, Russian researchers were already actively engaged in studying HEAs, publishing papers, and participating in international conferences. Researchers are particularly interested in the potential to discover properties in metals that are not typically found in conventional materials. This could include new forms of magnetic properties, electrical conductivity, superplasticity, unique stability at high temperatures, and other characteristics that not only overcome the limitations of traditional materials but also open doors to creating entirely new technologies and innovative applications. These discoveries may be the key to developing more effi cient and advanced materials for use in a wide range of industries, from energy to medicine. However, it is important to note that research on high-entropy alloys is still in its early stages, and further investigation and development are required to fully realize its potential and determine specifi c areas of application. The purpose of this work is to review the latest advancements in HEAs, its properties, methods of fabrication, and applications, as well as to identify the most promising directions for further research. Research objectives: 1) to review modern methods of obtaining HEAs; 2) to study the infl uence of alloying elements on the properties of HEAs; 3) to evaluate the properties of coatings based on HEAs; 4) to study the corrosion resistance of HEAs; 5) to study the heat resistance of HEAs; 6) to study the strength and plastic properties of HEAs; 7) to study the electrical conductivity and magnetic properties of HEAs; 8) to determine promising areas of application of HEAs.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 Research Methods This paper presents the results of a literature review of studies on HEAs. The research focuses on developments primarily from 2020 to 2024, conducted by both domestic and foreign scientists. Various methods of obtaining HEAs were studied to determine the most predominant. Given the high interest of researchers in both the corrosion-resisting properties of alloys in general and the properties of coatings in particular, the largest part of the review is devoted to this issue. The study also includes works on improving the heat resistance, strength, ductility, electrical conductivity, and magnetic properties of HEAs. Based on an analysis of statistical data obtained from the interdisciplinary free scientifi c database Scilit, which indexes scientifi c materials, there has been a signifi cant increase in publications and research on HEAs in recent years. This indicates growing interest in the topic and makes the current period particularly relevant for analysis in this fi eld. The data analysis was conducted as of August 2024. More detailed dynamics of the number of publications on the topic “High-entropy alloys” are illustrated using the bar graph in Fig. 1, which shows the number of publications by year of release. The presented statistical data indicate that research in the fi eld of HEAs has experienced signifi cant growth in recent years. Since 2004, the number of publications on this topic has gradually increased, with the most noticeable surge occurring after 2015. From 2015 to 2024, the number of publications increased more than tenfold, indicating growing interest in this fi eld of research. This rapid growth may be due to both the expansion of knowledge in the fi eld of HEAs and increased attention to the topic from the scientifi c community. Currently, many research groups around the world, including in the USA, Japan, South Korea, China, and Europe, are actively studying HEAs. These groups not only conduct fundamental research but also develop new production methods, improve material properties, and expand its areas of application. Hundreds of scientists and engineers worldwide are deeply engaged in this area of materials science. Today, around 100 countries actively participate in the development and study of HEAs, indicating that this fi eld of science and technology attracts attention from researchers from all over the world, contributing to a deeper understanding and unlocking the potential of these materials. To visually demonstrate the geographic diversity of interest in HEAs, Fig. 2 presents a list of countries and the number of publications, which allows to assess each country’s contribution to this research area. Fig. 1. The number of publications on the topic “High-entropy alloys” depending on the year of publication
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 Fig. 2. The number of publications on the topic “High-entropy alloys” in diff erent regions China leads in the number of publications, signifi cantly ahead of other countries. The USA ranks second, although its contribution is substantially smaller. India, Germany, and Japan follow, demonstrating moderate activity in this fi eld. South Korea and Russia have comparable numbers of publications. The United Kingdom, France, and Australia round out the list. These data highlight the high relevance of the topic of high-entropy alloys in the global scientifi c community, with China being a notable leader. This review includes publications from diff erent regions, but most of the research was conducted at universities and research institutes in China. The choice to study the developments of foreign scientists, particularly in China, over the past four years is due to several factors: China is one of the leaders in HEAs research and development. The country actively conducts research in this fi eld, creating new alloys and production technologies. Studying foreign developments allows assessing the level of science in other countries, as well as using their experience and achievements to improve our own research. Results and Discussion Methods of Obtaining High-Entropy Alloys High-entropy alloys can be obtained using several approaches. Various technical solutions can be used, including melting processes, powder metallurgy (mechanical alloying of powders), welding, spinning, splat cooling, self-propagating high-temperature synthesis, magnetron sputtering of targets, and powder mixture surfacing on a metal base. The fi rst HEAs were produced by induction and arc melting followed by casting [1, 2]. This process involved melting various metallic components of the alloy using an induction or arc furnace, after which the molten material was poured into molds to create the desired shape and size. A. S. Rogachev in his study [3] notes that the most predominant methods of obtaining HEAs are: melt crystallization; mechanical alloying in planetary mills combined with spark plasma sintering; spark plasma sintering; combustion synthesis (SHS). In addition to the methods listed, which can be called classical, other methods of obtaining HEAs have emerged in recent years. Scientists at the State Key Laboratory for Advanced Metals and Materials reviewed all alloy production methods for coatings and studied HEAs properties. They noted that the most promising method is laser additive manufacturing, which off ers high technological precision [4]. The laser additive manufacturing method allows for the creation of complex three-dimensional structures of HEAs directly from powders or wire. Laser melting of the material with high precision and
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 process parameter control enables the production of alloys with specifi c microstructures and properties. In [5], a review of various alloys produced using laser additive manufacturing was conducted. It was noted that these alloys are characterized by rapid design and manufacture, as well as good thermophysical and mechanical properties. In [6], a CrMnFeCoNi HEA with outstanding wear-resistant and corrosion-resistant properties was produced using laser additive manufacturing and subsequent laser shock treatment. After laser treatment, the results showed a signifi cant improvement in performance. Specifi cally, the coeffi cient of friction and wear rate of the specimens were signifi cantly reduced. For example, the scratch height on the untreated specimen surface varied from 0 to 4.5 μm below the surface and up to 4.2 μm above it, while on the specimen treated with a 2 J laser, the height ranged from 0 to 4.2 μm below and up to 5.6 μm above the surface. At laser energies of 4 and 6 J, signifi cant ripple patterns and more pronounced microstructural changes were observed on the treated surfaces. Corrosion tests showed that the laser-treated specimens had lower corrosion current densities and higher corrosion potentials compared to untreated specimens, indicating improved corrosion resistance. Specifi - cally, the treated specimens exhibited a reduction in corrosion current to 0.1 μA/cm² and an increase in corrosion potential to −0.3 V, indicating the formation of denser passive fi lms capable of protecting the material from aggressive ions. The main conclusions of the work are that laser shock peening leads to the formation of a layer with increased microhardness and compressive residual stress, which in turn reduces wear and protects the material from corrosion. These improvements are due to grain refi nement and the creation of compressive residual stresses, which contribute to the formation of more durable passive fi lms. In a recent study conducted at the Siberian State Industrial University, an innovative arc surfacing method using fl ux-cored wire was discussed, off ering a new approach to HEAs fabricating. The method involves the use of specially designed fl ux-cored wires and high-silicon manganese fl ux for surfacing, allowing for the avoidance of issues associated with traditional powder methods. The study showed that the resulting metal primarily consists of iron and alloying elements, but certain challenges were identifi ed, such as the presence of non-metallic inclusions and relatively low hardness compared to equimolar HEAs. These results highlight both the potential and limitations of the new method, opening up prospects for further research and improvements in the fi eld of HEAs and its applications [7]. Alloying of High-Entropy Alloys One of the most promising methods for improving the properties of HEAs is alloying, a process of adding various elements to the base composition of the alloy. Alloying opens new possibilities for adapting HEAs to meet the specifi c requirements of diff erent industrial sectors. The authors will consider various properties of HEAs modifi ed by alloying. Alloying can signifi cantly infl uence the corrosion resistance of HEAs. Diff erent alloying elements can interact with the environment in various ways, leading to diff erent types of corrosion. In study [8], the eff ect of Mo on the microstructure, corrosion properties, and composition of the passive fi lm of cast AlCrFeNi3Mox (x = 0; 0.1; 0.2; 0.3; 0.4) was investigated. The Mo0.3 alloy has a corrosion rate of 0.0155 mm/year and exhibits superior corrosion resistance compared to the Mo alloy. The increased corrosion resistance is attributed to the superior protective properties of the passive fi lm with higher Cr2O3 content and embedded Mo oxides. In study [9], it was found that adding the appropriate amount of Co to replace Cr in the Fe35Ni20Cr20 alloy positively aff ects its corrosion resistance. Wear resistance improvement is achieved through alloying with boron [10], niobium [11], and tungsten carbide [12]. Alloying with boron (0.3 atomic percent) modifi es the microstructure and deformation mechanism of the alloy, leading to a 35-fold increase in wear resistance. The primary mechanism for this improvement is associated with the formation of nanostructured layers and changes in wear type under high loads. The study showed that adding niobium changes the alloy’s microstructure, signifi cantly increasing hardness and wear resistance but reducing corrosion resistance. Maximum wear resistance was observed at a niobium content of 1.5 mol. % while the wear coeffi cient decreased to 84 % at loads of 10 N and 20 N compared to the original alloy without niobium. Adding 5–20 % tungsten carbide (WC) to the CrFeCoNi
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 high-entropy alloy signifi cantly improves its mechanical properties. The alloy’s hardness increases, and its corrosion resistance and wear resistance are enhanced. Particularly eff ective was the addition of 20 % WC, which resulted in a signifi cant increase in overall corrosion resistance and a wear reduction of approximately 4.5 times. For better comparison, the research results are presented in a Table 1. This table provides data on the wear rate of various HEAs before and after alloying. These data allow us to evaluate the eff ectiveness of alloying in improving the wear resistance of HEAs. Ta b l e 1 Wear rate of high-entropy alloys before and after alloying High entropy alloy Metal for alloying Characteristics before alloying Characteristics after alloying Load, N Wear rate, mm 3/ (N·m) Load, N Wear rate, mm3/(N·m) CoCrFeNi [10] B 2 2.6 × 10−5 2 8.3 × 10−6 5 2.9 × 10−5 5 8.6 × 10−5 8 3.57 × 10−4 8 8.9 × 10−5 AlCr2FeCoNi [11] Nb 5 18.7 × 10−6 5 5.2 × 10−6 10 46.8 × 10−6 10 6.5 × 10−6 20 40 × 10−6 20 6.2 × 10−6 CrFeCoNi [12] W 5 1.7 × 10−4 5 3.8 × 10−5 From the data presented, it can be seen that alloying signifi cantly improves the wear resistance of HEAs. For example, for CoCrFeNi alloy, alloying with boron (B) reduced the wear rate from 2.6 × 10⁻⁵ to 8.3 × 10⁻⁶ mm³/(N m) under 2 N load. Similarly, adding niobium (Nb) to the AlCr2FeCoNi alloy signifi cantly reduced the wear rate from 18.7 × 10−6 to 5.2 × 10−6 mm³/(N·m) under 5 N load. Adding tungsten (W) to CrFeCoNi also showed a signifi cant reduction in the wear rate from 1.7 × 10−4 to 3.8 × 10−5 mm³/(N m) under 5 N load. These results confi rm that alloying is an eff ective method for enhancing the wear resistance of high-entropy alloys, making it more suitable for use under conditions of high loads and intense wear. Alloying high-entropy alloys with elements such as Nb [13], La [14], Y [15] signifi cantly improves its thermal stability by altering the microstructure and chemical composition. These elements promote the formation of thermodynamically stable phases and protective oxide fi lms, which prevent grain growth, reduce atomic diff usivity, and protect the material from oxidation and corrosion. As a result, HEAs become more resistant to high temperatures and aggressive operating conditions, expanding its applications in various high-tech industries, such as aerospace, energy, and automotive industries. A study on the temperature dependence of the mechanical properties of Co20Cr20Fe20Mn20Ni20, Co19Cr20Fe20Mn20Ni20C1, and Co17Cr20Fe20Mn20Ni20C3 alloys in the range of 77 to 473 K, conducted by scientists from Tomsk [16], revealed that carbon alloying signifi cantly aff ects its structural and mechanical characteristics. Alloying leads to an increase in the lattice parameter of the austenitic phase, an increase in the yield strength, and a strengthening of the temperature dependence of strength due to solid solution, grain boundary, and dispersion strengthening, especially in the heterophase alloy Co17Cr20Fe20Mn20Ni20C3. While single-phase alloys demonstrate improved mechanical properties and plasticity at low temperatures, the heterophase alloy becomes more brittle, despite an increase in strength. Alloying HEAs with elements such as titanium (Ti) [17], aluminum (Al) [18], and neodymium (Nd) [19] plays a key role in improving its strength properties. Titanium contributes to increased hardness and deformation resistance, aluminum improves thermal stability and corrosion resistance, and adding neodymium enhances mechanical characteristics such as strength and ductility. These improvements make
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 HEAs more eff ective for use in high-load and critical areas such as aerospace, automotive, and energy industries. The addition of C and Mo [20] to the alloy contributes to the improvement of its ductility. Carbon and molybdenum can be used for microalloying the alloy, which promotes the formation of fi ne carbide phases in the material structure. These carbides can act as barriers to dislocation movement, enhancing the alloy’s ductility. Hydrogen can also be used to improve alloy ductility by reducing resistance to plastic deformation [21, 22]. Dissolved hydrogen can change the energy of defect formation in the material, which in turn can enhance its ability for plastic deformation. Alloying with Zn [23] and Cu [24] plays a key role in modifying the electrical conductivity of highentropy alloys. This opens the potential for developing energy-saving technologies, electrical conductors, sensors, and electronic components. The change in conductivity properties depends on the alloy composition, temperature, pressure, and the presence of impurities, highlighting the importance of alloying in the modifi cation process of these materials. The fatigue characteristics of high-entropy aluminum-based Al0.5CoCrFeNi alloy thin fi lms with diff erent aluminum additions were also investigated. The results showed that additionof aluminumcaneff ectively reduce the localizationof cyclicdeformations and improve fatigue resistance, which is associated with the reduction of cyclic slip irreversibility [25]. The study [26], also noted that with the addition of Al to the FeCoNiTiAlx coating, the hardness of the coating increased, and it demonstrated better wear resistance. Alloying plays an important role in modifying various properties of HEAs. Various elements such as molybdenum, cobalt, boron, niobium, tungsten carbide, titanium, aluminum, neodymium, carbon, copper, and zinc are used to improve the corrosion resistance, wear resistance, thermal stability, strength, plasticity, and conductive properties of high-entropy alloys (fi g. 3). Fig. 3. Improving the properties of high-entropy alloys by alloying Thus, alloying represents a powerful tool for modifying high-entropy alloys to achieve specifi c desired properties and expand its application areas. Coatings and its Properties Methods of Obtaining Coatings from HEAs Studying the materials published in both Russian and foreign sources over the past few years, it becomes obvious that scientists are interested in obtaining thin fi lms and coatings from HEAs. This conclusion is also confi rmed by the study [27], which highlights a signifi cant increase in the study of HEAs fi lms and coatings and surface modifi cation by various methods over the last fi ve years.
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 HEA-based coatings are currently of great interest in materials science due to its compositional freedom and excellent properties, such as excellent hardness and impact toughness, high wear resistance, corrosion and oxidation resistance, and exceptional thermal stability [28]. The methods of applying HEA coatings play a key role in determining its fi nal properties and areas of application. The choice of coating technology directly infl uences the microstructure, phase composition, adhesion to the substrate, as well as the mechanical and functional characteristics of the coating. In recent years, there has been signifi cant interest in the development and improvement of various methods for applying HEA coatings, driven by its unique properties, such as high hardness, wear and corrosion resistance, thermal stability, and mechanical strength. The main methods for applying HEA coatings include laser surfacing, magnetron sputtering, as well as nitriding and oxidation of substrates. Each of these methods has its own advantages and features that make it suitable for diff erent applications and operating conditions. Coatings of high-entropy FeNiCoAlCu alloy obtained by laser surfacing demonstrate high wear resistance. The results of the studies showed that such coatings have good thermal stability at temperatures below 780 °C. It is also noted that it demonstrates good wear characteristics at high temperatures, mainly due to the formation of oxide fi lms on the surface of the coating. The wear mechanisms are predominantly abrasive and oxidative [29]. High-entropy ceramic fi lms obtained by nitriding or oxidizing HEAs substrates exhibit good anti-wear, anti-radiation, anti-corrosion, and anti-oxidation properties. These properties make it attractive for use in extreme conditions, such as high temperature, high strength, and intense radiation [30]. Magnetron sputtering allows the production of HEA fi lms with improved properties. For example, FeCoNiCuAl fi lm obtained by magnetron sputtering exhibits enhanced corrosion and magnetic properties compared to the bulk alloy of similar composition. Studies show that such fi lms have better corrosion resistance than its bulk counterparts [31]. Properties of HEA Coatings The corrosion resistance, magnetic properties, and microstructure of the surfaced and annealed fi lms were investigated. Results show that the surfaced HEA has better corrosion resistance than the bulk HEA of the same composition. The most relevant and notable developments in the fi eld of anti-corrosion properties of coatings are reviewed by international experts in work [32]. In a study conducted by the authors [33], HEA coatings based on FeCoCrNiMoTiW composition, produced by mechanical alloying, were studied. The results showed that the hardness of these coatings exceeds the hardness of most stainless steels by 1.5–2 times, and the dry friction coeffi cients are in the range of 0.08–0.16. This signifi cant diff erence in friction coeffi cients of HEA coatings is due to its nanostructural features and the manifestation of the size dependence of its properties. Thus, the study demonstrated the potential of these coatings in terms of mechanical properties. In the study [34], a comparison was made between HEA coating and steel specimens. Researchers noted that the nanostructured FeCrNiTiZrAl coating has signifi cantly greater hardness and wear resistance compared to stainless steels. Moreover, the friction coeffi cient of the FeCrNiTiZrAl coating is signifi cantly lower than that of other materials, which contributes to an increased service life of products with such coatings. Study [35] showed that the HEA Al0.6CoCrFeNiTi is a promising material for metal thermal insulation coatings due to its combination of low thermal conductivity and high thermal stability. Overall, studies on the properties of HEA coatings have demonstrated its unique properties and potential applications. The results of the studies confi rm the potential of HEAs in the fi eld of mechanical properties, anti-corrosion properties and thermal insulation properties. Thus, HEA coatings may become promising materials for various industries, including aviation, automotive manufacturing, and biomedical industry. Corrosion Resistance of High-Entropy Alloys Corrosion is one of themain causes of material failure in various industries, such as energy, petrochemical, and marine engineering. Therefore, studying the corrosion resistance of HEAs is critical for its use in
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 extreme operating conditions. This section is dedicated to analyzing the corrosion properties of HEAs and the mechanisms of its corrosion resistance. The study [36] showed that the addition of aluminum to high-entropy FeCoCrNiAlx (x = 0.1; 0.3) alloy improves its mechanical properties and reduces weight. The eff ect of aluminum on the corrosion behavior and properties of alloy fi lms in H2SO4 solutions was analyzed. Results showed that increasing aluminum content improves corrosion resistance in H2SO4 solution. The study [37] evaluated the corrosion resistance of high-entropy FeCoNiCr alloy coatings obtained by electrochemical deposition. The coatings synthesized from Fe, Co, Ni, and Cr sulfate solutions formed a crack-free, granular surface with a grain size ranging from 500 nm to 5 μm. Electrochemical measurements demonstrated high corrosion resistance of the coatings in various environments, including NaCl, H2SO4, and NaOH solutions. The study highlights the potential of these coatings for engineering applications due to its excellent corrosion resistance. The paper [38] examines the eff ect of ultrasonic shot peening on the corrosion resistance and antibacterial properties of the high-entropy Al0.3Cu0.5CoCrFeNi alloy. The primary goal of the study was to eliminate the contradictions between the corrosion resistance and antibacterial properties of the alloy by using ultrasonic shot peening. The results of the study confi rmed that ultrasonic shot peening improved the corrosion resistance and antibacterial properties of the high-entropy Al0.3Cu0.5CoCrFeNi alloy. Electrochemical tests showed that ultrasonic shot peening contributed to the formation of a more protective passive fi lm, reducing the corrosion current density. Scientists have developed a new high-entropy AlTiVCrCu0.4 alloy, which has low density and high hardness. The study showed that the dual-phase high-entropy AlTiVCrCu0.4 alloy has unique mechanical and corrosion properties due to its complex structure consisting of BCC and HCP phases. The alloy exhibits outstanding corrosion resistance in aggressive environments, which is associated with the formation of a protective metal oxide fi lm [39]. The study [40] examines the eff ect of cold rolling and annealing on the corrosion properties of Al2Cr5Cu5Fe53Ni35 alloy, focusing on grain size changes and its impact on corrosion behavior. The results show that reducing grain size improves the localized corrosion resistance of the material. The developed alloy demonstrates improved anti-corrosion properties, making it promising for marine applications. The best corrosion resistance was observed with 85 % thickness reduction and a 3-minute annealing period. The noble behavior of the material is maintained in solutions with varying seawater concentrations. The eff ect of cold rolling and post-deformation annealing on the properties of the high-entropy CrMnFeCoNi alloy was studied [41]. The results showed that the grain size decreased from 207.5 μm to 4.6 μm. Microhardness, yield strength, and tensile strength increased by 28 %, 68 %, and 24 %, respectively, but the percentage elongation decreased from 59.3 % to 43.8 %. The strengthening mechanisms are associated with grain refi nement and increased dislocation density. The corrosion resistance of the alloy also improved due to a decrease in grain size and residual compressive stress. The paper [42] examines the eff ect of friction stir processing on the corrosion resistance of high-entropy CoCrFeNiCu alloy. Friction stir processing involves the use of a rotating tool that moves across the surface of the material, generating high temperatures and mechanical stresses. This results in plastic deformation and mixing of the metal, which reduces the grain size of the alloy, improving its strength and ductility. After processing, the alloy becomes more resistant to corrosion due to the formation of a more stable protective fi lm on its surface. The study [43] investigated the eff ect of thermal shocks on the microstructure, microhardness, and corrosion properties of VCrFeTa0.2W0.2 alloy with reduced activation. After thermal shocks, the content of diff erent phases in the alloy changed, microhardness increased, and corrosion resistance improved. The alloy demonstrated excellent properties under harsh environmental conditions, making it a promising material for nuclear construction. The studies conducted show that adding various elements, improving the methods of synthesis and processing of alloys, and optimizing the structure can improve the corrosion resistance of materials. Another
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 important factor is the infl uence of various processing and annealing technologies on the microstructure and properties of alloys. Studies show that optimizing these parameters can signifi cantly improve the corrosion resistance of materials. Heat Resistance and Thermal Stability of High-Entropy Alloys Heat resistance and thermal stability play a crucial role in the development of HEAs, which are a promising class of materials with unique properties. This section will explore the key aspects related to the resistance of these alloys to high temperatures and thermal cycling. It will analyze the infl uence of alloy composition, processing, and microstructure on its thermal properties, as well as discuss methods to improve the heat resistance and stability of HEAs. In recent years, considerable attention of foreign researchers has been attracted by the development of refractory HEAs, which are considered as a promising class of materials for high-temperature applications. These alloys possess unique mechanical properties and have the potential to replace traditional nickelbased superalloys in the next generation of technologies [44]. Particular attention in the research is paid to the use of electrodeposited nanostructured alloys such as NiFeCoW, NiFeCoMo and NiFeCoMoW. These materials have high thermal and structural stability at elevated temperatures and show a signifi cant increase in hardness after annealing. Electrodeposition is an eff ective and aff ordable method for synthesizing nanostructured alloys, providing high thermal stability [45]. Another important aspect is the use of methods aimed at improving thermal stability. Among these, longterm annealing and high-pressure torsion (HPT) are of particular importance. Long-term annealing promotes the recrystallization of the material, enhancing its properties [46]. HPT is an eff ective technological process for changing the shape and structure of materials by rotating under pressure, applied in various industries, including metallurgy, plastics, and composites [47]. The study [48] demonstrated that replacing molybdenumwith vanadium in HEAs has a signifi cant impact on its structural and thermal properties. This approach leads to the formation of crystalline complex nitride particles in a ribbon structure, which positively aff ects thermal stability and helps stabilize supercooled liquids in alloys with a fully amorphous structure. Additionally, the study [49] confi rms that the thermal stability of the high-entropy Cr0.8FeMn1.3Ni1.3 alloy is signifi cantly dependent on the aging temperature. When treated at 300 °C, the alloy microstructure remains stablewithminimal changes inmechanical properties. However, at higher temperatures (500 and 700 °C), a complex phase decomposition is observed, which signifi cantly aff ects its mechanical characteristics. These results highlight the need for strict control of heat treatment parameters to achieve optimal properties of HEAs for various engineering applications. In conclusion, research in the fi eld of HEAs continues to expand our understanding of its potential for high-temperature applications. Overall, studies in this fi eld continue to open new horizons for creating materials with optimized properties for future technologies. Strength and Plasticity Properties of HEAs This section reviews the latest advances in developing and improving the strength and plasticity properties of HEAs, including methods of synthesis and processing, as well as the application of modern technological approaches and modeling. Development of New Alloys with Embedded High-Strength Properties The development of new alloys with embedded high-strength properties is actively underway. A lightweight, refractory alloy AlNb2TiV with a density of 6.19 g/cm³ and a specifi c yield strength of 167 MPa·cm³/g was proposed. The alloy demonstrates good deformability [50]. In another study, a matrix composite Re0.5MoNbW(TaC)0.5 was successfully synthesized from a HEA. The composite microstructure remained stable after annealing at 1,300 °C for 168 hours. It showed remarkable high-temperature strength, with a yield strength of about 901 MPa and a true compressive strength of about 1,186 MPa at 1,200°C [51]. The composite creates an ideal balance between ultra-high strength and high plasticity at elevated
OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 temperatures. This discovery may be an important contribution to theoretical research and applications in high-temperature anti-softening. High yield strength and ultimate strength were noted in a study on Mo-based HEAs. The compressive yield strength of the M20 alloy reaches up to 1,285 MPa, the ultimate strength is 2,447 MPa, and the elongation is 27 % [52]. Recent research conducted at Belgorod State University [53] resulted in the development of a new HEA, Co40Mo28Nb25Hf7, which demonstrated outstanding mechanical properties at high temperatures. This alloy, produced by vacuum arc remelting, includes BCC and Laves C14 phases, as well as a small amount of hafnium oxides. Studies have shown that the alloy has a high yield strength at room temperature (1,775 MPa) and retains signifi cant strength at 1,000 °C (600 MPa). In the temperature range of 22–1,000 °C, its specifi c strength surpasses many commercial superalloys and other HEAs, highlighting its potential for high-temperature applications. Methods for Improving Strength Properties Improving the strength properties of HEAs can be achieved by various methods, each of which is aimed at optimizing the microstructure and phase composition of the materials. One such method is the introduction of new gradient nanoscale structures of dislocation cells into a stable single-phase face-centered cubic (FCC) lattice. The face-centered cubic (FCC) lattice is a crystalline structure in which atoms are located at the corners and in the center of each face of the cube. This confi guration provides the material with high plasticity and the ability to deform. Dislocation cells, being areas of local deformation in the crystal lattice, create additional resistance to dislocation movement, which increases the strength of the material without an obvious loss of plasticity [54]. The process of introducing such structures includes thermomechanical treatment, controlled cooling, or the use of nanoscale additives that promote the formation of dislocation cells with specifi c characteristics. As a result, HEAs with FCC lattices and gradient structures demonstrate improved performance, making them promising for use under high loads. Another method is cold rolling followed by laser surface heat treatment. Cold rolling is a process of deforming a material at low temperatures, which strengthens the material due to the increase in the density of dislocations. Laser surface heat treatment involves the use of a laser for local heating and subsequent cooling of the material, which allows to modify its microstructure and improve mechanical properties [55]. Spinodal decomposition, which causes compositional heterogeneity in the structure, is the process of separating a solid solution into two phases with diff erent chemical compositions. As a result of spinodal decomposition, nanometer-scale structures are formed that strengthen the material. This compositional heterogeneity signifi cantly enhances the mechanical characteristics of HEAs, making it stronger and more reliable for use under high loads and temperatures [56]. The use of laser additive manufacturing for coherent strengthening of alloys is another eff ective method. Laser additive manufacturing is a technology where material is added layer by layer using a laser. This method allows precise control of the microstructure and phase composition of the material, leading to improved strength properties [57]. Thus, the implementation of these methods signifi cantly improves the strength properties of HEAs, ensuring high strength and maintaining plasticity, making it promising for use in various high-load and high-temperature applications. Property Prediction and Modeling Research into increasing the strength of HEAs is of strategic importance for creating advanced materials that combine strength, low density, and resistance to various operational conditions. Research can be found on predicting the strength of HEAs, in particular based on machine learning. Machine learning (ML) is a branch of artifi cial intelligence that trains computer systems to perform tasks without being explicitly programmed to do so. Instead of using explicit instructions, machines learn from data and algorithms, identifying patterns and making predictions or decisions. In the fi eld of materials science and nanotechnology, multiscale modeling has become an essential tool for understanding material properties across diff erent levels – from atomic to macroscopic. The use of
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