The Pacific National University, Khabarovsk, Russia

E. Kh. Ri, Director of the Higher School of Industrial Engineering of the Polytechnic Institute, Doctor of Technical Sciences, e-mail: erikri999@mail.ru
М. А. Ermakov, Associate Professor of the Higher School of Industrial Engineering of the Polytechnic Institute, Candidate of Technical Sciences, e-mail: ermakovma@yandex.ru
Е. D. Кim, Associate Professor of the Higher School of Industrial Engineering of the Polytechnic Institute, Candidate of Technical Sciences, e-mail: jenya_1992g@mail.ru
К. V. Doroshenkо, Postgraduate Student of the Higher School of Industrial Engineering of the Polytechnic Institute, e-mail: rbhbkk1212@yandex.ru

Modern research on high-entropy alloys is aimed at studying the effect of composition and energy impacts on their microstructure and properties. The method of self-propagating high-temperature synthesis has advantages such as low cost, speed and simplicity compared to traditional methods for producing high-entropy alloys, however, in the absence of external influences, microdefects remain in the alloy structure. The energetic interaction of short-pulse electromagnetic fields with a strength of 105–107 V/m with a metallic liquid contributes to the destruction of its structure, increase of the solubility of modifying and alloying elements and the uniformity of their distribution. The purpose of this work was to study the effect of nanosecond electromagnetic pulses on the structure formation, hardness, and microhardness of the structural components of the Al – Ti – Cr – Ni – V – Zr system high–entropy alloys synthesized by self-propagating high-temperature synthesis. The structural components in the alloy of the Al – Ti – Cr – Ni – V – Zr system with nanosecond electromagnetic pulses amplitude from 0 to 40 kV have been identified by electron microscopy and element–phase analysis. It is determined that the structural components of this high-entropy alloy are complex-alloyed solid solutions of four types: a white solid solution, BCC(1) type solid solutions of light and dark gray colors, and a dark solid solution without zirconium. The amplitude dependence of the change in the content of elements in the structural components of the alloy of the Al – Ti – Cr – Ni – V – Zr system has been established. With an increase in the nanosecond electromagnetic pulses amplitude to 20 kV, the content of aluminum in the studied solid solutions of all types and of vanadium and chromium in solid solutions without zirconium increase significantly, and the concentrations of the remaining elements are practically independent of the nanosecond electromagnetic pulses amplitude. The maximum value of the microhardness of BCC(1) type solid solutions and a solid solution without zirconium is observed when irradiating a melt with nanosecond electromagnetic pulses with an amplitude of 20 kV.
The study was conducted at the Shared Research Facility “Applied Materials Science” of the Pacific State University with the financial support of the Ministry of Science and Education of the Russian Federation within the framework of Research project No. AAAAA-A20-120021490002-1.

1. Yeh J.-W., Chen S.-K., Lin S.-J., Gan J.-Y. et al. Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes. Advanced Engineering Materials. 2004. Vol. 6, Iss. 5. pp. 299–303.
2. Cantor B., Chang I. T. H., Knight P., Vincent A. J. B. Microstructural development in equiatomic multicomponent alloys. Materials Science and Engineering: A. 2004. Vol. 375–377. pp. 213–218.
3. Gludovatz B., Hohenwarter A., Catoor D., Chang E. H. et al. A fractureresistant high-entropy alloy for cryogenic applications. Science. 2014. Vol. 345, Iss. 6201. pp. 1153–1158.
4. Youssef K. M., Zaddach A. J., Niu C., Irving D. L., Koch C. C. A novel lowdensity, high-hardness, high-entropy alloy with close-packed single-phase nanocrystalline structures. Materials Research Letters. 2015. Vol. 3, Iss. 2. pp. 95–99.
5. Lee C. P., Chen Y. Y., Hsu C. Y., Yeh J. W., Shih H. C. The effect of boron on the corrosion resistance of the high entropy alloys Al0.5CoCrCuFeNiBx. Journal of the Electrochemical Society. 2007. Vol. 154, No. 8. pp. 424.
6. Stepanov N. D., Yurchenko N. Yu., Gridneva A. O., Zherebtsov S. V. et al. Structure and hardness of B2 ordered refractory AlNbTiVZr0.5 high entropy alloy after high-pressure torsion. Materials Science and Engineering: A. 2018. Vol. 716. pp. 308–315.
7. Zhi Q., Tan X., Liu Zh., Liu Y. et al. Effect of Zr content on microstructure and mechanical properties of lightweight Al2NbTi3V2Zrxr high entropy alloy. Micron. 2021. Vol. 144. 103031. DOI: 10.1016/j.micron.2021.103031
8. Yang X., Zhang Y., Liaw P. K. Microstructure and compressive properties of NbTiVTaAlx high entropy alloys. Procedia Engineering. 2012. Vol. 36. pp. 292–298.
9. Hsu C.-Y., Yeh J.-W., Chen S.-K., Shun T.-T. Wear resistance and high-temperature compression strength of Fcc CuCoNiCrAl0.5Fe alloy with boron addition. Metallurgical and Materials Transactions A. 2004. Vol. 35. pp. 1465–1469.
10. Cao Y., Liu Y., Liu B., Zhang W. et al. Effects of Al and Mo on high temperature oxidation behavior of refractory high entropy alloys. Transactions of Nonferrous Metals Society of China. 2019. Vol. 29, Iss. 7. pp. 1476–1483.
11. Gorr B., Mueller F., Christ H.-J., Mueller T. et al. High temperature oxidation behavior of an equimolar refractory metal-based alloy 20 Nb – 20 Mo – 20 Cr – 20 Ti – 20 Al with and without Si addition. Journal of Alloys and Compounds. 2016. Vol. 688, Part B. pp. 468–477.
12. Yao H., Liu Y., Sun X., Lu Y. et al. Microstructure and mechanical properties of Ti3V2NbAlxNiy low-density refractory multielement alloys. Intermetallics. 2021. Vol. 133. 107187. DOI: 10.1016/j.intermet.2021.107187
13. Stepanov N. D., Yurchenko N. Yu., Skibin D. V., Tikhonovsky M. A., Salishchev G. A. Structure and mechanical properties of the AlCrx r NbTiV (x = 0, 0.5, 1, 1.5) high entropy alloys. Journal of Alloys and Compounds. 2015. Vol. 652. pp. 266–280.
14. Yurchenko N. Y., Stepanov N. D., Zherebtsov S. V., Tikhonovsky M. A., Salishchev G. A. Structure and mechanical properties of B2 ordered refractory AlNbTiVZrx r ( x = 0–1.5) high-entropy alloys. Materials Science and Engineering: A. 2017. Vol. 704. pp. 82–90.
15. Wan B., Li X.-Q., Pan C.-L., Li D.-Y. et al. Microstructure and mechanical properties of TiAl/Ni-based superalloy joints vacuum brazed with Ti – Zr – Fe – Cu – Ni – Co – Mo filler metal. Rare Metals. 2021. Vol. 40. pp. 2134–2142.
16. Jia Z., Gao Z.-X., Ji J.-J., Liu D.-X. et al. High-temperature deformation behavior and processing map of the as-cast Inconel 625 alloy. Rare Metals. 2021. Vol. 40. pp. 2083–2091.
17. Senkov O. N., Wilks G. B., Scott J. M., Miracle D. B. Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys. Intermetallics. 2011. Vol. 19, Iss. 5. pp. 698–706.
18. Senkov O. N., Scott J. M., Senkova S. V., Miracle D. B., Woodward C. F. Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy. Journal of alloys and compounds. 2011. Vol. 509, Iss. 20. pp. 6043–6048.
19. Senkov O. N., Senkova S. V., Dimiduk D. M., Woodward C. F., Miracle D. B. Oxidation behavior of a refractory NbCrMo0.5Ta0.5TiZr alloy. Journal of Materials Science. 2012. Vol. 47. pp. 6522–6534.
20. Wu Y. D., Cai Y. H., Wang T., Si J. J. et al. A refractory Hf25 f Nb25Ti25Zr25
high-entropy alloy with excellent structural stability and tensile properties. Materials Letters. 2014. Vol. 130. pp. 277–280.
21. Lin C.-M., Juan C.-C., Chang C.-H., Tsai C.-W., Yeh J.-W. Effect of Al addition on mechanical properties and microstructure of refractory AlxHfNbTaTiZr alloys. Journal of Alloys and Compounds. 2015. Vol. 624. pp. 100–107.
22. Poletti M. G., Fiore G., Szost B. A., Battezzati L. Search for high entropy alloys in the X-NbTaTiZr systems (X = Al, Cr, V, Sn). Journal of Alloys and Compounds. 2015. Vol. 620. pp. 283–288.
23. Tong C.-J., Chen M.-R., Yeh J.-W., Lin S.-J. et al. Mechanical performance of the AlxCoCrCuFeNi high-entropy alloy system with multiprincipal elements. Metallurgical and Materials Transactions A. 2005. Vol. 36. pp. 1263–1271.
24. Zhang K. B., Fu Z. Y., Zhang J. Y., Wang W. M. et al. Microstructure and mechanical properties of CoCrFeNiTiAlx high-entropy alloys. Materials Science and Engineering: A. 2009. Vol. 508, Iss. 1–2. pp. 214–219.
25. Wang X. F., Zhang Y., Qiao Y., Chen G. L. Novel microstructure and properties of multicomponent CoCrCuFeNiTix alloys. Intermetallics. 2007. Vol. 15, Iss. 3. pp. 357–362.
26. Jinhong P., Ye P., Hui Z., Lu Z. Microstructure and properties of AlCrFe-CuNix (0.6 ≤ x ≤ 1.4) high-entropy alloys. Materials Science and Engineering: A. 2012. Vol. 534. pp. 228–233.
27. Rogachev A. S. Structure, stability and properties of high-entropy alloys. Fizika metallov i metallovedenie. 2020. Vol. 121. No. 8. pp. 807–841.
28. Sanin V. N., Yukhvid V. I., Ikornikov D. M., Andreev D. E. et al. SHS-metallurgy of cast high-entropy alloys based on transition metals. Doklady Akademii nauk. 2016. Vol. 470, No. 4. pp. 421–426. DOI: 10.7868/S0869565216280124
29. Znamensky L. G., Ivochkina O. V., Kulakov B. A., Krymsky V. V. Electropulse and ultrasonic processing of materials in precision casting. Chelyabinsk : Publishing House of the South Ural State University, 2010. 259 p.
30. Balakirev V. F., Krymsky V. V., Ri E. Kh., Ri Kh., Shaburova N. A. Electric pulse treatment of metal melts; edited by Academician of the Russian Academy of Sciences L. A. Smirnov. Khabarovsk : Publishing House of the Pacific National University, 2014. 142 p.
31. Deev V. B., Ri E. Kh., Prusov E. S., Ermakov M. A., Goncharov A.V. Modification of cast aluminum alloys of the Al – Mg – Si system by treatment of the liquid phase with nanosecond electromagnetic pulses. Izvestiya vuzov. Tsvetnaya metallurgiya. 2021. Vol. 27, No. 4. pp. 32–41. DOI: 10.17073/0021-3438-2021-4-32-41
32. Andersson J.-O., Helander T., Hоglund L., Shi P., Sundman B. Thermo-Calc and DICTRA, computational tools for materials science. Calphad. 2002. Vol. 26, Iss. 2. pp. 273–312.
33. GOST 2912–79. Technical chromium oxide. Specifications. Introduced: 01.01.1980.
34. GOST 4168–79. Sodium nitrate. Specifications. Introduced: 01.01.1980.
35. GOST 6058–73. Aluminum powder. Specifications. Introduced: 01.01.1975.