Obrabotka Metallov. 2016 no. 1(70)

ОБРАБОТКА МЕТАЛЛОВ № 1 (70) 2016 50 МАТЕРИАЛОВЕДЕНИЕ Abstract Features of structure and phase composition of the powders of Ti and Nb after mechanical activation are investi- gated by the methods of X-ray diffraction, scanning electron microscopy and energy-dispersive microanalysis. The powders were mixed in mass ratio 60 % Ti and 40 % Nb in planetary mill AGO-2C during 10, 15 and 20 minutes. Water-cooled camera was used to reduce the temperature of the process. It is shown that during the process of me- chanical activation the powder of two-component composition is obtained. During the process of severe plastic de- formation and mixing particles of Ti and Nb are combined into larger objects. The agglomerates with scale structure are formed. The size distribution of powder particles is characterized by bimodal type. Most particles have a size from 10 to microns. A smaller part of formed particles has a size of about 100 microns. As a result of treatment time increasing the scatter of the powder granulometric composition is reduced with shifting to lower values. It was ob- served that during activation time increase the content of Nb saluted in Ti increases and reaches composition Ti37Nb at 20 minutes of activation. Ti and Nb are equilibrium distributed inside the particles. Herewith the main β-phase forms rom phases of initial components. β-phase is the substitutional solid solution of Ti and Nb. The β-phase quantity increases with the activation time increasing. The phase of initial α-Ti is retained in the alloy throughout the treatment time. Increasing of treatment time or using of additive factors which enhance the effect of mechanical activation is necessary to complete the process of monophase alloy formation. It is shown in conclusion that the form and granulometric composition of obtained Ti-Nb alloy powder, its phase composition with equilibrium distribution of components allow use it in additive technology of selective laser sintering. Keywords: titanium, niobium, mechanical activation, powder mixture, aglomeration, mechanical alloying, phase composition, Ti-40Nb alloy. DOI: 10.17212/1994-6309-2016-1-42-51 References 1. Boldyrev V.V. Mekhanokhimiya i mekhanicheskaya aktivatsiya tverdykh veshchestv [Mechanochemistry and mechanical activation of solids]. Uspekhi khimii – Russian Chemical Reviews, 2006, vol. 75, no. 3, pp. 203–215. (In Russian) 2. Kuz’mich Yu.V., Kolesnikova I.T., Serba V.I., Freidin B.M. Mekhanicheskoe legirovanie [Mechanical alloy- ing]. Moscow, Nauka Publ., 2005. 213 p. 3. Zhuravleva K., Bönisch M., Prashanth K.G., Hempel U., Helth A., Gemming T., Calin M., Scudino S., Schul- tz L., Eckert J., Gebert A. Production of porous β-type Ti–40Nb alloy for biomedical applications: comparison of selective laser melting and hot pressing. Materials , 2013, vol. 6, iss. 12, pp. 5700–5712. doi: 10.3390/ma6125700 4. Zhuravleva K., Chivu A., Teresiak A., Scudino S., Calin M., Schults L., Eckert J., Gebert A. Porous low modu- lus Ti40Nb compacts with electrodeposited hydroxyapatite coating for biomedical applications. Materials Science and Engineering: C , 2013, vol. 33, iss. 4, pp. 2280–2287. doi: 10.1016/j.msec.2013.01.049 5. Babakova E.V., Gradoboev A.V., Saprykin A.A., Ibragimov E.A., Yakovlev V.I., Sobachkin A.V. Comparison of activation technologies powder ECP-1 for the synthesis of products using SLS. Applied Mechanics and Materials, 2015, vol. 756, pp. 220–224. doi: 10.4028 /www.scientific.net/AMM.756.220 6. Saprykin A.A., Ibragimov E.A., Yakovlev V.I. Influence of mechanical activation of powder on SLS process. Applied Mechanics and Materials , 2014, vol. 682, pp. 143–147. doi: 10.4028 /www.scientific.net/AMM.682.143 7. Zhao D., Chang K., Ebel T., Nie H., Willumeit R., Pyczak F. Sintering behavior and mechanical properties of a metal injection molded Ti–Nb binary alloy as biomaterial. Journal of Alloys and Compounds , 2015, vol. 640, pp. 393–400. doi: 10.1016/j.jallcom.2015.04.039 8. Popova A.A., Sobachkin A.V., Nazarov I.V., Yakovlev V.I., Loginova M.V., Sitnikov A.A. Dynamic diffrac- tometry of phase transformations during high-temperature synthesis in mechanically activated powder systems in the thermal explosion mode. Bulletin of the Russian Academy of Sciences: Physics , 2013, vol. 77, iss. 2, pp. 120–122. doi: 10.3103/S1062873813020275 9. Evstigneev V.V., Smirnov E.V., Afanas’evA.V., Filimonov V.Yu., Yakovlev V.I., Loginova M.V. Dinamicheskii teplovoi vzryv v mekhanicheski aktivirovannykh poroshkovykh smesyakh [Dynamic thermal explosion in mechani- cally activated powder mixtures]. Polzunovskii vestnik – Polzunov Bulletin, 2007, no. 4, pp. 162–167. 10. Nouri A., Hodgson P.D., Wen C. Effect of ball-milling time on the structural characteristics of bio- medical porous Ti–Sn–Nb alloy. Materials Science and Engineering: C , 2011, vol. 31, iss. 5, pp. 921–928. doi: 10.1016.j.msec.2011.02.011