Obrabotka Metallov 2015 No. 4

ОБРАБОТКА МЕТАЛЛОВ № 4 (69) 2015 111 МАТЕРИАЛОВЕДЕНИЕ Abstract Investigations aimed at identifying the changes in the surface layer of titanium alloy VT6 after combined treat- ment are carried out. Combined surface treatment of titanium alloy VT6 includes alloying with plasma formed during electrical explosion of titanium foil with a powder weight quantity of boron carbide and subsequent irradiation by high-intensity pulse electronic beam of sub millisecond exposure time. The titanium foil is used as exploded conduc- tor during electroexplosive alloying. A weight quantity of boron carbide powder is placed into explosion area over the titanium foil. The laboratory electroexplosive device EVU 60/10 is used for EEA (electroexplosive alloying).The main parameters for a pulse liquid-phase alloying are set by the value of the charging voltage of the energy storage device of the accelerator, the diameter of the nozzle channel and the distance from its section to the sample. Sub- sequent thermal treatment of the titanium alloy VT6 surface layer is performed with high-intensity pulse electronic beam at the SOLO device (Institute of High Current Electronics SB RAS). The study found that electroexplosive alloying of the surface layer of titanium alloy VT6 samples leads to the formation of the highly developed relief. In the surface layer a heterogeneous distribution of alloying elements is observed through the methods of electron scanning microscopy. A significant difference in its concentration in the revealed layers leads to the difference in its strength and tribological properties. The subsequent electron beam treat- ment of the alloyed surface leads to its smoothing. The formation of the multilayer structure occurs and the distribu- tion of alloying elements in the surface layer becomes more uniform. Analysis of the treated surface irradiated by the electron beam revealed the presence of two characteristic elements of the structure, formed in the result of the subsequent treatment with high-intensity pulse electron beam. The first structure element is acicular structure areas with the needle size of 1-10 microns. Studies of the transverse sections of the titanium alloy after combined treat- ment allowed to determine the thickness of the modified layer, which is not more than 30 μm. So, we can conclude that electroexplosive alloying and fast cooling at pulse treatment lead to the formation of a structure of submicro- nanoscale level that can improve the strength and tribological properties of the treated surface. Keywords : titanium, boron carbide, electric explosion alloying electron-beam treatment, structural-phase states. DOI: 10.17212/1994-6309-2015-4-102-112 References 1. Kolachev B.A., Elagin V.I., Livanov V.A. Metallovedenie i termicheskaya obrabotka tsvetnykh metallov i splavov [Metallurgy and heat treatment of non-ferrous metals and alloys]. 3 rd ed. Moscow, MISIS Publ., 1999. 416 p. ISBN 5-87623-027-8 2. Tian Y.S., Chen C.Z., Li S.T., Huo Q.H. Research progress on laser surface modification of titanium alloys. Applied Surface Science , 2005, vol. 242, iss. 1–2, pp. 177–184. doi: 10.1016/j.apsusc.2004.08.011 3. Il’in A.A., Kolachev B.A., Pol’kin I.S. Titanovye splavy: sostav, struktura, svoistva. Spravochnik [Titanium alloys: composition, structure, properties. Reference book]. Moscow, VILS-MATI Publ., 2009. 520 p. 4. Boyer R.R., Briggs R.D. The use of β titanium alloys in the aerospace industry. Journal of Materials Engineering and Performance , 2005, vol. 14, iss. 6, pp. 681–685. doi: 10.1361/105994905X75448 5. Polmear I., John D. Light alloys. From traditional alloys to nanocrystals . 4 th ed. Butterworth-Heinemann, 2005. 416 p. ISBN 978-0-7506-6371-7 (Russ. ed.: Polmear Ya . , Dzhon D. Legkie splavy: ot traditsionnykh do nanokristallov . Moscow, Tekhnosfera Publ., 2008. 463 p. ISBN 978-5-94836-174-1). 6. Bagautdinov A.Ya., Budovskikh E.A., Ivanov Yu.F., Gromov V.E. Fizicheskie osnovy elektrovzryvnogo legirovaniya metallov i splavov [Physical bases electroexplosive alloying metals and alloys]. Novokuznetsk, SibGIU Publ., 2007. 301 p. ISBN 978-5-8441-0263-9 7. Poletika I.M., Krylova T.A., Makarov S.A. Ispol’zovanie elektronno-luchevoi obrabotki dlya sozdaniya uprochnyayushchikh pokrytii [Use electron-beam processing to create a hardening coatings]. Izvestiya Tomskogo politekhnicheskogo universiteta – Bulletin of the Tomsk Polytechnic University , 2011, vol. 319, no. 2, pp. 94–98. (In Russian) 8. Ivanov Yu.F., Kobzareva T.Yu., Raikov S.V., Gromov V.E., Soskova N.A., Budovskikh E.A. Surface hardening alloy VT6 of electric explosion and by electron beam. AIP Conference Proceedings , 2014, vol. 1623, pp. 217–220. doi: 10.1063/1.4901482 9. Raikov S.V., et al. Formirovanie strukturno-fazovykh sostoyanii i svoistv poverkhnosti titanovykh splavov pri elektrovzryvnom legirovanii i posleduyushchei elektronno-puchkovoi obrabotke [Formation of structurally-