https://www.elibrary.ru/title_about_new.asp?i 1605-8119 17 1 2013 1-91

RAR RUS 1-5 Materials and Energy Research Center (MERC) Behzad Aminikia

Tehran, Iran

Materials and Energy Research Center (MERC) Youzbashi

Tehran, Iran

Effect of milling time on mechanochemical synthesis of nanocrystalline zirconium diboride Zirconium diboride (ZrB2) is the material suitable for high performance applications. It has high melting point and high hardness value. On the other hand, recently, mechanical activation and mechanical milling have been extensively used for synthesis of advanced materials. In this present research, nanocrystalline ZrB2 was produced using mixtures of zirconium dioxide, boric acid and pure magnesium as raw materials via mechanochemical process. The phase transformation and structural evolution characterization during process were utilized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. A thermodynamic appraisal showed that the reaction between ZrO2, H3BO3 and Mg is highly exothermic and should be self-sustaining. XRD analyses exhibited that the nanocrystalline ZrB2 was formed after 60 h milling time. The results indicate that increasing milling time up to 40 h had no significant effect other than refining the crystallite size. mechanochemical; nanocrystalline; transmission electron microscopy; Zirconium diboride; Zirconium dioxride https://mpm.spbstu.ru/article/2013.28.1/ MPM_2013_17_1_P01.pdf

RAR RUS 6-10 Tarbiat Modares University Soleymani

Tehran, Iran

Tarbiat Modares University Abdollah-Zadeh

Tehran, Iran

Tarbiat Modares University Alidokht

Tehran, Iran

Microstructural and tribological properties of ultra fine grained hybrid composite produced by friction stir processing Ultra fine grained (UFG) Al5083 based hybrid composite reinforced by SiC and MoS2 particles was prepared by Friction Stir Processing (FSP). A constant tool travel speed of 50 mm/min and different rotation speeds from 630 up to 1600 rpm were used. The microstructure of the Al based composite were investigated and compared to base metal and FSPed samples. It was found that although FSP resulted in decreasing the mean grain size of the base metal to about 2 µm, the addition of reinforcing particles in microstructure led to the more decrease in grain size of the alloy. An ultra fine grained hybrid composite with 500 nm grain size was obtained through rotation speed of 1250 rpm. Moreover, this hybrid composite showed the highest wear resistance and hardness in comparison to all samples due to the modification of microstructure and the addition of particles. ultra fine grained materials; Friction Stir Processing; hybrid composite; wear https://mpm.spbstu.ru/article/2013.28.2/ MPM_2013_17_1_P02.pdf

RAR RUS 11-16 Malek Ashtar University of Technology Sodaee

Isfahan, Iran

Malek Ashtar University of Technology Ghasemi

Isfahan, Iran

Malek Ashtar University of Technology Paimozd

Isfahan, Iran

Remarkable influence of terbium cations on the magnetic properties of cobalt ferrite nanoparticles Terbium substituted cobalt ferrite with composition of CoFe2-xTbxO4 nanoparticles (x = 0-0.5) were prepared employing a reverse micelle process. The effect of Tb3+ cations substitution on structural and magnetic properties of cobalt ferrite nanoparticles was investigated. X-ray diffraction and field-emission scanning electron microscopy evaluations demonstrated that single phase spinel ferrites with narrow size distribution were obtained. The particle size was beyond the range of superparamagnetic range. Vibrating sample magnetometer was employed to probe the magnetic properties of the samples. It was found that with an increase in terbium content, the coercive field decreases while the saturation of magnetization increases. The Mössbauer spectroscopy was used to determine the site preference of constitutive elements. It is interesting to find that adding terbium cations could enhanced saturation magnetization of cobalt ferrite and make it as a suitable candidate for recording head. cobalt ferrite; terbium cation; reverse micelle; magnetic properties https://mpm.spbstu.ru/article/2013.28.3/ MPM_2013_17_1_P03.pdf

RAR RUS 17-21 Tarbiat Modares University Mojtahedi

Tehran, Iran

Tarbiat Modares University Shahverdi

Tehran, Iran

Iranian National Center for Laser Science and Technology (INLC) Torkamany

Tehran, Iran

Surface treatment of nano-structured steel with pulsed lasers In this paper, the laser surface treatment of Fe52Cr18Mo7B16C4Nb3 alloy has been investigated with the use of pulsed Nd:YAG laser, and the optimum pulse duration parameter for having finer microstructure, highest hardness and the most homogeneous surface has been studied. Melt profile and structure of laser processed samples were investigated by use of optical and field emission scanning electron microscopes and X-ray diffraction (XRD). Moreover, the mean crystallite size of laser treated zones was studied by the Scherrer formula. Hardness of the samples was measured by means of microhardness testing device. Results showed that by decreasing the laser pulse duration and power density in the surface of the laser treated zone the highest amount of the hardness can be achieved. Moreover, peak broadening phenomenon was observable in XRD patterns of samples with lower pulse duration. It is due to the increasing of thermal gradient in the surface as a result of decreasing power density. nano-structured steel; pulsed Nd:YAG laser; laser surface treatment https://mpm.spbstu.ru/article/2013.28.4/ MPM_2013_17_1_P04.pdf

RAR RUS 21-28 Isfahan University of Technology Ranjbar

Isfahan, Iran

Isfahan University of Technology Kameli

Isfahan, Iran

Isfahan University of Technology Salamati

Isfahan, Iran

Coalescence threshold temperature in Ag nanoisland growth by pulsed laser deposition In this study, Ag nanoislands were deposited on glass and Si(100) at substrate temperature from 25 to 450 °C by Pulsed Laser Depositions (PLD). The growth of Ag nanoislands was evidenced from optical absorption surface plasmon resonance (SPR) bands. SPR peaks was not evidently observed in the spectrum of sample deposited at 25 °C, but sample deposited at 150 °C presented a broad SPR peak around λ=870 nm. SPR peak showed a blue shift to 540-550 nm and became narrower as the substrate temperature increases. Atomic Force Microscope (AFM) showed that by increasing deposition temperature to 350 and 450 °C, Ag islands grow in height and diameter and the number of island decrease among the surface. Two-probe measurement of electrical resistance of films was also recorded during deposition processes to recognize the coalescence of Ag nanoislands. The results show that the deposition at temperatures below 250 °C leads to a sharp decrease in film resistance while at higher temperatures the islands were separated without resistance decline. To determine coalescence threshold temperature, resistance variation was measured for a cooling substrate, from 300 down to 200 °C, substrate. The result revealed that the coalescence of Ag begins near 230 °C. Ag nanoisland; PLD; coalescence; SPR; resistance measurement https://mpm.spbstu.ru/article/2013.28.5/ MPM_2013_17_1_P05.pdf

RAR RUS 29-32 Ferdowsi University of Mashhad Ksravi-Nouri

Iran

Ferdowsi University of Mashhad Shahtahmassebi

Iran

Ferdowsi University of Mashhad Attaran-Kakhki

Iran

Ferdowsi University of Mashhad Zohuri

Iran

Fabrication and characterization of silver-tin dioxide core-shell structured nanocomposite particles Core-shell structure nanoparticles with silver core and tin dioxide shell were synthesized via a facile soft-chemical process. Optical absorption spectra of tin dioxide deposited silver core nanoparticles, obtained by UV-Visible spectroscopy, showed distinct shifts, both in peak position and its intensity, compared with bare silver nanoparticles, which indicated that silver-tin dioxide core-shell nanoparticles appeared to be formed. The core-shell structure formation was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD pattern showed distinct major peaks corresponding to cubic silver and minor peaks due to tetragonal tin dioxide phases. TEM results, from which we could estimate the nanoparticles size as well as their shell thickness, demonstrated that thin tin dioxide shells encapsulated the silver core particles. silver; tin dioxide; core-shell; nanoparticles; nanocomposite https://mpm.spbstu.ru/article/2013.28.6/ MPM_2013_17_1_P06.pdf

RAR RUS 33-37 Tarbiat Modares University Belbasi

Tehran, Iran

Tarbiat Modares University Ramezani

Tehran, Iran

The effect of sandblasting time on producing nanocrystalline surface of PO733 steel (DIN: 1.8509) Techniques to produce nanostructured materials are severe plastic deformation (SPD) and surface severe plastic deformation (SSPD). This paper reports our study on severe plastic deformation that applied on samples surfaces with sandblasting by hard particles of silica and then annealing. The samples were made of nitriding steel PO733 (DIN: 1.8509). The grain size of the nanocrystalline surface layer was in the range of 20 nm, determined by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Mechanical behavior of nanocrystalline surface was investigated using micro hardness test. The result show grain size decreases to nanometer scale (even 15 nm), by increase time of sandblasting, but this decreasing is not linear. Thickness of nanocrystalline surface is independent by time of sandblasting and its stable. It was demonstrated that the mechanical behavior of samples surface was markedly improved when its grain size was reduced to nanoscale. The nanocrystalline surface caused by the sandblasting and annealing treatment exhibited considerably higher hardness. PO733 steel (DIN: 1.8509); nanocrystalline surface; mechanical properties; sandblasting https://mpm.spbstu.ru/article/2013.28.7/ MPM_2013_17_1_P07.pdf

RAR RUS 38-46 University of Tartu Kondratiev

Tartu, Estonia

University of Tartu Kink

Tartu, Estonia

F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru

St.Petersburg, Russia

Low temperature sol-gel technique for processing Al-doped Zinc Oxide films In this work, Al-doped Zinc Oxide (AZO) films are prepared by sol-gel method. Films are highly transparent with transmittance over 90 % at 550 nm. Film parameters are studied varying film thicknesses. Different substrates are used, such as technical glass or Si. Typical film thicknesses are less than 500 nm. In order to optimize the technology for processing of transparent electrode materials based on AZO, influence of aluminium content, annealing time/temperature and annealing environment on the film resistivity are studied. For film characterization 4-probe resistance method, optical spectrophotometry, SEM and energydispersive X-ray spectroscopy, are used. sol-gel technique; Al-doped Zinc Oxide (AZO) films; transparent electrode materials https://mpm.spbstu.ru/article/2013.28.8/ MPM_2013_17_1_P08.pdf

RAR RUS 47-62 Shivaji University Chougale

India

Hanyang University Han

Seoul, South Korea

Radiation & Photochemistry Division, Bhabha Atomic Research Centre Rath

India

Shivaji University Fulari

India

Synthesis, characterization and surface deformation study of nanocrystalline Ag2Se thin films Herein we report electrochemical synthesis of the silver selenide (Ag2Se) thin films using simple and economical electrodeposition method in potentiostatic mode at room temperature (∼ 27 °C). Growth of rhombohedral Ag2Se nanocrystals having size 63 to 75 nm were observed in (201) direction. Band gap energy of Ag2Se decreased from 1.3 eV to 1.1 eV and contact angle increases from 58° to 74° with increase in bath concentration from 3 to 5 mM. A possible mechanism for the growth and stress of compact granular Ag2Se nanocrystals is discussed with DEHI technique. Compared with previous methods, present method shows simple and easiest way to synthesize nanosized Ag2Se particles in one step. electrodeposition SEM Q-size effect DEHI stresses https://mpm.spbstu.ru/article/2013.28.9/ MPM_2013_17_1_P09.pdf

RAR RUS 59-70 Tula State University Treschov

Tula, Russian Federation

Tula State University Delyagin

Tula, Russian Federation

Simulation of shell made of isotropic different resistance graphite using volumetric finite elements considering connectedness of stresses and temperatures The method of construction of a new finite element for calculation different resistant material in the temperature field has been considered. The data of calculations of a spherical shell of graphite using finite element method have been presented. finite element method; isotropic different resistant material; a spherical shell made of graphite https://mpm.spbstu.ru/article/2013.28.10/ MPM_2013_17_1_P10.pdf

RAR RUS 71-91 N-7717-2016 7005519053 0000-0003-4116-4821 Institute of Problems of Mechanical Engineering RAS Kolesnikova Anna anna.kolesnikova.physics@gmail.com

St. Petersburg, Russia

Ioffe Institute Soroka

St.Petersburg, Russia

F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru

St.Petersburg, Russia

Defects in the elastic continuum: classification, fields and physical analogies In the framework of continuum mechanics of solids the classification of the defects, i.e. the internal sources of elastic fields, is presented. The classification is based on the dimension of the area where the defect eigenstrain is given. On the base of the elastic fields of the infinitesimal dislocation loops the fields of various defects: localized line segment, the ray, the circular dilatation thread, and the circular dilatation disk are found. The fields for the axisymmetric defects are given in the form of Lipschitz-Hankel integrals. defects in the elastic medium; defect eigenstrain; elastic fields; infinitesimal dislocation loops; circular dilatation thread; circular dilatation disk https://mpm.spbstu.ru/article/2013.28.11/ MPM_2013_17_1_P11.pdf