13th International Conference on Fracture June 16–21, 2013, Beijing, China -3- layer structure after nanostructuring by the beam of Zr+ ions is represented by phases of FeZr 3, FeZr2, as well as ferrite grains. The average size of the grains in the surface layer is 100-150 nm (fig. 1, b-d). 2.1.2. Specimensnanoindentation Strength properties of the specimens under study before and after the treatment were evaluated by nanoindentation to penetrate at the depth of 200 nm. It is revealed that due to nanostructuring the hardness of the surface layer increases approximately by 1.5 times. At the same time elastic modulus is reduced almost by 2 times. 2.1.3. X-raydiffraction For specimens in the initial state structure is primarily represented by the α-Fe iron, whereas after nanostructuring the formation of intermetallic phases of the system Fe-Zr: FeZr2 and FeZr3, as well as the carbides ZrC into the subsurface layer takes place. Structural-phase micro-analysis of the specimen surface with nanostructured surface layer was performed. The data indicate that the overall content of zirconium in the subsurface layer of the specimen makes about 14.2 %. 2.2. Study of the modified surface layer of 30CrMnSiNi2 steel Investigations of surface layer of 30CrMnSiNi2 steel specimens performed with the use of SEM have allowed to reveal nanosized particles in the modified layer (fig. 1,a). Average size of the particles made 80-10 nm. The particles are non-uniformly distributed over the specimen surface. The thickness of the modified surface layer was also estimated to show the depth of 2 µm (fig. 1,b). X-ray microanalysis has shown that iron in the layer has α-structure, while Zr-containing phases are as well revealed there. a)
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