Obrabotka Metallov 2013 No. 4

ОБРАБОТКА МЕТАЛЛОВ № 4 (61) 2013 26 МАТЕРИАЛОВЕДЕНИЕ Obrabotka metallov N 4(61), October–December 2013, Pages 19-27 Investigation of the structure and phase composition of the nitrided layers of martensitic steel produced by ultrasonic burnishing and ion implantation 1,2 Zh.G. Kovalevskaya, 3 V.A. Kukareko 1 National Research Tomsk Polytechnic University, Lenin Avenue, 30, Tomsk, 634050, Russia 2 Institute of Strength Physics and Materials Science of the Siberian Branch of the Russian Academy of Sciences, pr. Akademicheskii, 2/4, Tomsk, 634021, Russia 3 Joint Institute of Mechanical Engineering of the National Academy of Sciences of Belarus, Akademicheskaya str., 12, Minsk, 220072, The Republic of Belarus E-mail: kovalevskaya@ispms.tsc.ru Received 25 October 2013 Revised 10 November 2013 Accepted 14 November 2013 Abstract The structure and phase composition of the nitrided layers of steel 40X13 received by intensive low-energy ion implantation of nitrogen and combined effect of ultrasonic burnishing and implantation are investigated by optical metallography, X-ray analysis and durometer. It is shown that ion implantation of nitrogen in steel 40X13 forms ni- tride hardened surface layer. Structure and phase composition of this layer depend on implantation temperature and the initial structure. After implantation at 350 °С nitrided layer is a diffusion zone containing nitrogen martensite and nitride particles. As a result of implantation at temperature 400 °С formed nitrided layer consists of nitride and diffusion zone. As a result of implantation at 450 °С and 500 °С chromium nitride is formed as well as iron nitride. The implanted layer has the following structure. The top layer - is the nitride layer with the highest values of microhardness up to 19000 MPa. Then there is a zone of internal nitriding of the second kind with high values of microhardness up to 15000 MPa. Next there is a zone of internal nitriding of the first kind with micro-hardness gradually decreased to 4500 MPa. High implantation leads to the release in the nitrided layer, mainly chromium nitride particles. Combined treatment of the steel, including ultrasonic burnishing and implantation, provides over the entire temperature range formation the nitrided layers with greater depth. This is due to the intensification of diffusion processes through the preliminary modification of the surface layer of the steel. Keywords: ultrasonic burnishing, high-intensity low-energy ion implantation of nitrogen, nitrided layer, phase composition, microhardness. References 1. Lahtin Yu.M., Kogan Ya.D. Azotirovanie stali [Nitrided steels]. Moscow, Mashinostroenie, 1976. 256 p. 2. Bokshtejn S.Z. Diffuzija i struktura metallov [Diffusion and structure of metals]. Moscow, Metallurgija, 1973. 208 p. 3. BelyjA.V., KukarekoV.A., PatejukA. Inzhenerijapoverhnostej konstrukcionnyhmaterialov koncentrirovannymi potokami ionov azota [Engineering surfaces of structural materials concentrated streams of nitrogen ions]. Minsk, Belorusskaja nauka, 2007. 244 p. 4. DidenkoA.N., Sharkeev Yu.P., Kozlov Je.V. RjabchikovA.I. Jeffekty dal’nodejstvija v ionno-implantirovannyh metallicheskih materialah [Long-range effects in ion-implanted metallic materials]. Tomsk, NTL Publ., 2004. 328 p.