Fabrication of the Nb–16Si Alloy Powder for Additive Technologies by Mechanical Alloying and Spheroidization in Electric-Arc Discharge Thermal Plasma
- 16 Downloads
The development of new, more refractory heat-resistant materials for gas-turbine engines is one of most important problems of modern materials science. This is associated with the fact that nickel superalloys currently used for this purpose have a lower melting point of ~1400°C, which limits their own maximal working temperature by a range of 1100–1150°C. The Ni alloys can be replaced by natural composites, in which refractory metals are a matrix, while their silicides are intermetallic hardeners. Only three “refractory metal–silicon” binary systems manifest stability to the Me5Si3 silicide, notably, Nb5Si3, Re5Si3, and W5Si3. From the viewpoint of a combination of a high melting point and a low density, the Nb5Si3 compound is optimal among other silicides. The use of alloys of the Nb–Si system in additive manufacturing machines is of considerable interest. This work presents the results of experimental investigations into the treatment of the Nb–16 at % Si powder fabricated using mechanical alloying of elemental Nb and Si powders in the thermal plasma flux. The Nb–16Si alloy powder is fabricated by the mechanical alloying of powders of pure elements in a Fritsch Pulverisette 4 planetary mill. The powder spheroidization is performed in a plasma installation based on a discharge vortex-stabilized electric-arc thermal plasma generator. Based on the results of experimental investigations, the principal possibility to perform the plasma spheroidization of particles of the Nb–16Si alloy prepared by mechanical alloying is shown. It is shown that the surface of spheroidized particles is rough and reflects the cast material structure. Three phase components Nb5Si3, Nb3Si, and Nbss having different optical contrast are revealed in microslices, which is confirmed by X-ray phase analysis.
Keywords:mechanical alloying spheroidization thermal plasma heat-resistant alloy spherical powder
This study was supported by the Russian Scientific Foundation, project no. 15-13-00062.
- 1.Svetlov, I.L., High-temperature Nb-Si composites, Materialovedenie, 2010, no. 9, pp. 29–38.Google Scholar
- 2.Karpov, M.I., Modern research directions and achievements in the field of development of new heat-resistant materials on the basis of refractory metals with intermetallic and carbide hardening, in: Nanotehnologii funkcional’nykh materialov (NFM’16): Trudy mezhdunarodnoi nauchno-tehnicheskoi konferentsii (Nanotechnologies of functional materials (NFM’16): Proc. Int. Sci. Tech. Conf.), St. Petersburg: SPb Gos. Tech. Univ., 2016, pp. 350–354.Google Scholar
- 3.Drawin, S. and Justin, J.F., Advanced lightweight silicide and nitride based materials for turbo-engine applications, Aerospace Lab., 2011, vol. 3, pp. 1–13.Google Scholar
- 5.Drawin, S., Ultra high temperature materials for turbines, European Framework Programme FP6–Specific Targeted Research Project (STREP) Priority T4–Aeronautics and Space: Final Activity Report, 2008.Google Scholar
- 6.Karpov, M.I., Vnukov, V.I., Korzhov, V.P., Stroganova, T.S., Zheltyakova, I.S., Prokhorov, D.V., Gnesin, I.B., Kiiko, V.M., Kolobov, Y.R., Golosov, E.V., and Nekrasov, A.N., Structure and mechanical properties of a eutectic high-temperature Nb–Si alloy grown by planar crystallization, Deform. Razrush. Mater., 2012, no. 12, pp. 2–8.Google Scholar
- 7.Svetlov, I.L., Kuz’mina, N.A., Neiman, A.V., Ishadzhanova, I.V., Karpov, M.I., Stroganova, T.S., Korzhov, V.P., and Vnukov, V.I., Effect of the crystallization rate on the microstructure, phase composition, and strength of Nb/Nb5Si3 in-situ composite, Izv. Ross. Akad. Nauk, ser. Fiz., 2015, vol. 79, no.9, pp. 1294–1297.Google Scholar
- 9.Drawin, S., P/M manufacturing of niobium silicide based materials, in: Proc. of 18 Plansee Seminar 2013–Int. Conf. on Refractory Metals and Hard Materials, Reutte/Austria, 2013, RM105.Google Scholar
- 16.Zverev, S.G., Research and development of high-frequency plasma systems for the treatment of refractory dispersed materials, Extended Abstract of Cand. Sci. (Eng.) Dissertation, St. Petersburg: SPb Gos. Tekh. Univ., 2002.Google Scholar
- 17.Alekseev, N.V., Samokhin, A.V., and Tsvetkov, Yu.V., RF Patent 2311225, 2007.Google Scholar