Institute of Structural Macrokinetics and Materials Science of Russian Academy of Sciences, Chernogolovka, Russia:

V. N. Sanin, Leading Researcher, e-mail: svn@ism.ac.ru
D. M. Ikornikov, Research Engineer
V. I. Yukhvid, Head of Laboratory

National University of Science and Technology “MISiS”, Moscow, Russia:
E. A. Levashov, Head of a Chair of Powder Metallurgy and Functional Coatings

Equimolar nickel aluminides (NiAl) have a good balance of chemical and physical properties (low density, high thermal conductivity, high oxidation resistance etc). Therefore, NiAlbased alloys are considered as prospective materials for creation of new high-temperature structural materials for turbine-type power units. Nowadays, NiAl-based materials have low hightemperature strength, and their plasticity with normal temperatures is limited. Improvement of mechanical properties of alloys, based on brittle intermetallide NiAl matrix can be reached by the following operations:
— alloying by plastic refractory metals (Cr, W, Mo, Re etc), forming a quasi-binary eutectics with NiAl;
— creation of composite structures (introduction or in-situ formation of ceramic particles or fibers of Al₂O₃, SiC, Y₂O₃, etc).
These approaches can increase a plasticity and high temperature strength of such materials. However, structure and properties of these alloys are very sensitive to composition and obtaining method. At the same time, obtaining technologies often have a laboratory scale. Therefore, the problem of creation of new structural NiAl-based materials is still relevant and has not been solved yet. This work is aimed on the study of possibility of obtaining of cast alloys in Ni – Al – B system with high B-concentration, by means of SHS-metallurgy (in combustion mode). Both researched compounds have a composite structure, where the matrix is formed by NiAl-based solid solution and embedded inclusions of τ-boride Ni₂₀Al₃B₆ and lamellar precipitates of complex boride (Mo, Cr) B. This work can be regarded as first positive experience of obtaining of composite materials, based on NiAl/τ-borides by means of SHS-metallurgy.

1. Bannykh O. A., Povarova K. B. Intermetallidy – novyy klass legkikh zharoprochnykh i zharostoykikh materialov (Intermetallides — new grade of light heat-resistant materials). Tekhnologiya legkikh splavov = Technology of light alloys. 1992. No. 5. pp. 26–32.

2. Povarova K. B., Filin S. A., Maslenkov S. B. Fazovye ravnovesiya s uchastiem -fazy v sistemakh Ni – Al – Me (Me – Co, Fe, Mn, CuO) pri 900 i 1100 ^оC (Phase equilibriums with participation of β-phase in Ni – Al – Me (Me – Co, Fe, Mn, CuO) systems with the temperature of 900 and 1100 ^оC). Metally = Metals. 1993. No. 1. pp. 191–205.
3. Sheng L. Y., Guo J. T., Tian Y. X., Zhou L. Z., Ye H. Q. Microstructure and mechanical properties of rapidly solidified NiAl – Cr(Mo) eutectic alloy doped with trace Dy. Journal of Alloys and Compounds. 2009. Vol. 475, Iss. 1/2. pp. 730–734.
4. Li H. T., Wang Q., He J. C., Guo J. T., Ye H. Q. β-Ti(M) solid solution formation and its thermal stability in a NiAl – Cr(Mo) – (Hf,Ti) near eutectic alloy. Materials Characterization. 2008. Vol. 59, Iss. 10. pp. 1395–1399.
5. Frommeyer G., Rablbauer R., Schäfer H. J. Elastic properties of B2-ordered NiAl and NiAl–X (Cr, Mo, W) alloys. Intermetallics. 2010. Vol. 18, Iss. 3. pp. 299–305.
6. Bei H., George E. P. Microstructures and mechanical properties of a directionally solidified NiAl–Mo eutectic alloy. Acta Materialia. 2005. Vol. 53, Iss. 1. pp. 69–77.
7. Milenkovic S., Schneider A., Frommeyer G. Constitutional and microstructural investigation of the pseudobinary NiAl – W system. Intermetallics. 2011. Vol. 19, Iss. 3. pp. 342–349.
8. Nikolaev A. G., Levashov E. A., Povarova K. B., Titova T. F., Fomina O. N. Vliyanie legirovaniya TiC, NbC i TiN na zharostoykost splava NiAl, poluchennogo SVS-kompaktirovaniem (Influence of alloying of TiC, NbC and TiN on heat resistance of NiAl alloy, obtained by SHS-compacting). Fizika i khimiya obrabotki materialov = Physics and Chemistry of Materials Treatment. 1998. No. 3. pp. 78–81.
9. Povarova K. B., Nikolaev A. G., Levashov E. A., Kazanskaya N. K., Geminov V. P., Koshelyaeva V. G., Bochvar A. G. Poluchenie metodom SVS kompozitsiy NiAl s Y₂O₃ i TiN (Obtaing of composites of NiAl with Y₂O₃ and TiN by SHS method). Fizika i khimiya obrabotki materialov = Physics and Chemistry of Materials Treatment. 1994. No. 4/5. pp. 135–143.
10. Campbell C., Kattner U. A Thermodynamic Assessment of the Ni-Al-B System. Journal of Phase Equilibria. 1999. Vol. 20, Iss. 5. pp. 485–496.
11. Sigworth G. K. The Grain Refinement of Aluminum and Phase Relationships in the Al – Ti – B System. Metallurgical and Materials Transactions. 1984. Vol. 15A. pp. 277–282.
12. Kotzott D., Ade M., Hillebrecht H. Single crystal studies on boron-rich t-borides Ni_23–xM_xB₆ (M = Zn, Ga, In, Sn, Ir). The surprising occurrence of B₄-tetraheda as a normal case. Journal of Solid State Chemistry. 2010. Vol. 183, Iss. 10. pp. 2281–2289.
13. Hillebrecht H., Ade M. B₄ Tetrahedra for Aluminum Atoms — A Surprising Substitution in t-Borides Ni₂₀Al₃B₆ and Ni₂₀AlB₁₄. Angewandte Chemie International Edition. 1998. Vol. 37, Iss. 7. pp. 935–938.
14. Ade M., Kotzott D., Hillebrecht H. Synthesis and crystal structures of the new metal-richternary borides Ni₁₂AlB₈, Ni₁₂GaB₈ and Ni_10.6Ga_0.4B₆ — examples for the first B5 zig-zag chain fragment. Journal of Solid State Chemistry. 2010. Vol. 183. pp. 1790–1797.
15. Yukhvid V. I., Sanin V. N., Merzhanov A. G. The Influence of High Artificial Gravity on SHS Processes. Processing by Centrifugation. Editors: L. L. Regel, W. R. Wilcox. New York : Kluwer Academic, 2001. pp. 185–200.
16. Sanin V., Andreev D., Ikornikov D., Yukhvid V. Cast Intermetallic Alloys by SHS Under High Gravity. Journal of Acta physica polonica A. 2011. Vol. 120, Iss. 2. pp. 331–335.
17. Sanin V. N., Ikornikov D. M., Andreev D. E., Yukhvid V. I. Tsentrobezhnaya SVS-metallurgiya evtekticheskikh splavov na osnove alyuminida nikelya (Centrifugal SHS-metallurgy of nickel aluminium based eutectic alloys). Izvestiya vuzov : Poroshkovaya metallurgiya i funktsionalnye pokrytiya = Proceedings of Universities. Powder metallurgy and functional coatings. 2013. No. 3. pp. 35–42.
18. Merzhanov A. G. Protsessy goreniya i sintez materialov (Burning processes and synthesis of materials). Chernogolovka : Publishing House of Institute of Structural Macrokinetics and Materials Science of Russian Academy of Sciences, 1998. 512 p.
19. Merzhanov A. G. The Chemistry of SHS. Journal of Materials Chemistry. 2004. Vol. 14, No. 12. pp. 179–191.
20. Lyakishev N. P., Pliner Yu. L., Ignatenko G. F., Lappo S. I. Alyuminotermiya (Aluminothermy). Moscow : Metallurgiya, 1978. 424 p.
21. Kablov E. N., Buntushkin V. P., Morozova G. I., Bazyleva O. A. Osnovnye printsipy legirovaniya intermetallida Ni₃Al pri sozdanii vysokotemperaturnykh splavov (Basic principles of alloying of Ni3Al intermetallide in the time of creation of high-temperature alloys). All-Russian Scientific-Research Institute of Aviation Materials. Moscow, 1998. Available at : http://viam.ru/public/files/1998/1998-202531.pdf.
22. GOST 18898–89. Izdeliya poroshkovye. Metody opredeleniya plotnosti, soderzhaniya masla i poristosti (State Standard 18898-89. Powder products. Methods of definition of density, oil content and porosity). Introduced: January 01, 1991. (in Russian).
23. Tumanova G. I. Kinetika protsessov okisleniya pri vysokikh temperaturakh zharoprochnykh deformiruemykh splavov na nikelevoy osnove (Kinetics of processes of oxidation in the time of high temperatures of nickel-based heat-resistant deformed alloys). All-Russian Scientific-Research Institute of Aviation Materials. Moscow, 1998. Available at : http://viam.ru/public/files/1986/1986-199703.pdf.
24. Bloshenko V. N., Bokii V. A., Borovinskaya I. P. Regularities and mechanism for self-cleaning from impurity oxygen in obtaining molybdenum disilicide by SHS method. Combustion, Explosion and Shock Waves. 1985. Vol. 21, Iss. 2. pp. 202–208.