Started in 1985 Semimonthly
ISSN 1005-0302
CN 21-1315/TG
Impact factor:6.155

The journal has been awarded the excellent periodical in China, and its articles are covered by SCI, EI, CA, SA, JST, RJ, CSA, MA, EMA, AIA etc., PASCAL web. ISI web of Science,SCOPUS.

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      28 September 2009, Volume 25 Issue 05 Previous Issue    Next Issue
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    Articles
    Effect of Porosity on the Mechanical Properties and WearPerformance of 2% Copper Reinforced Sintered Steel Used in Shock Absorber Piston Production
    Bekir Yalcin
    J. Mater. Sci. Technol., 2009, 25 (05): 577-582. 
    Abstract   HTML   PDF (1503KB)

    Powder metallurgy (P/M) method has mainly been used to produce automobile parts such as self-lubrication beds, shock absorber parts, and gear wheels. In order to investigate the effect of porosity on the mechanical and tribological properties in sintered steel, specimens with 10%, 15%, and 20% porosity were produced in a 10 mm×10 mm×55 mm prismatic shape by pre-alloying powders of the MPIF Fe-C-0.205 alloy used in the production of shock absorber pistons. Sintering was carried out at 900°C for 45 min in an argon atmosphere. Tensile, charpy, and microhardness tests were performed on these specimens. In addition, the wear performance of a 2% Cu reinforced sintered steel alloy under dry sliding conditions was determined. Metallographic studies such as pore formation, worn surface, and fractured surface analyses were performed by scanning electron microscopy and optical microscopy. The results indicate that irregular pore formation tendencies increase with an increase in porosity (%). Furthermore, an increase in porosity was shown to decrease the mechanical properties and increase the wear trace area and the friction coefficient of sintered steel.

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    Experimental Investigation on the Performance of Armour Grade Q&T Steel Joints Fabricated by Flux Cored Arc Welding with Low Hydrogen Ferritic Consumables
    G. Magudeeswaran,V. Balasubramanian,G. Madhusudhan Reddy,G. Gopalakrishnan
    J. Mater. Sci. Technol., 2009, 25 (05): 583-591. 
    Abstract   HTML   PDF (1340KB)

    Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking (HIC) and softening in the heat affected zone (HAZ) after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy to avoid HIC because of higher solubility for hydrogen in austenitic phase. Recent studies revealed that low hydrogen ferritic (LHF) steel consumables can also be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits and required resistance against cold cracking. Hence, in this investigation an attempt has been made to study the performance of armour grade Q&T steel joints fabricated by flux cored arc welding with LHF steel consumables. Two different consumables namely (i) austenitic stainless steel and (ii) low hydrogen ferritic steel have been used to fabricate the joints by flux cored arc welding (FCAW) process. The joints fabricated by LHF consumable exhibited superior transverse tensile properties due to the presence of ferrite microstructure in weld metal. The joints fabricated by ASS consumable showed higher impact toughness due to the presence of austenitic phase in weld metal microstructure. The HAZ softening in coarse grain heat affected zone (CGHAZ) is less in the joints fabricated using LHF consumable due to the lower heat input involved during fabrication compared to
    the joints fabricated using ASS consumables.

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    Evaluation of the Electroslag Remelting Process in Medical Grade of 316LC Stainless Steel
    S. Ahmadi,H. Arabi,A. Shokuhfar,A. Rezaei
    J. Mater. Sci. Technol., 2009, 25 (05): 592-596. 
    Abstract   HTML   PDF (449KB)

    This study is focused on the effects of electroslag remelting by prefused slag (CaO, Al2O3, and CaF2) on macrostructure and reduction of inclusions in the medical grade of 316LC (316LVM) stainless steel. Analysis of the obtained results indicated that for production of a uniform ingot structure during electroslag remelting, shape and depth of the molten pool should be carefully controlled. High melting rates led to deeper pool depth and interior radial solidification characteristics, while decrease in the melting rates caused more reduction of nonmetallic inclusions. Large shrinkage cavities formed during the conventional casting process in the primary ingots were found to be the cause of the fluctuation in the melting rate, pool depth and extension of equiaxed crystals zone.

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    Effect of Aging Time and Temperature on Mechanical Properties and Microstructural Evolution of 2205 Ferritic-Austenitic Stainless Steel
    H. Keshmiri,A. Momeni,K. Dehghani,G.R. Ebrahimi,G. Heidari
    J. Mater. Sci. Technol., 2009, 25 (05): 597-602. 
    Abstract   HTML   PDF (1135KB)

    Duplex stainless steels (DSS) with ferritic{austenitic microstructures offer good combination of resistance to pitting corrosion and high strength that are not concomitantly attainable using conventional single phase austenitic or ferritic stainless steels. The DSS used in this investigation was 2205 alloy having a stable microstructure consisting of about 45% ferrite and 55% austenite at ambient temperature. In order to investigate aging behavior of this steel and the influences on mechanical properties, different aging treatments were conducted at temperatures of 350−950°C for various aging time of 15, 30, 60 and 180 min. The aged specimens were subjected to impact testing and hardness measurements. Finally, the changes in microstructure due to aging were studied by optical and scanning electron microscopy. The results showed that aging at temperatures lower than 550°C for different time had negligible effects on mechanical properties. Besides, no considerable changes in term of precipitation of harmful intermetallic particles were observed in microstructure below this temperature. However, a critical temperature range, 550−650 °C, was introduced here. Aging in this range led to a significant decrease in toughness and notable increase in hardness. The formation of intermetallic phases such as σ was recognized as the major reason for the observed changes.

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    Dynamic Recrystallization Behavior of a Fe-Cr-Ni Super-Austenitic Stainless Steel
    A. Hoseini Asliy,A. Zarei-Hanzaki
    J. Mater. Sci. Technol., 2009, 25 (05): 603-606. 
    Abstract   HTML   PDF (586KB)

    The super-austenitic stainless steels are extensively utilized in the seamless tubes production for oil extraction industries. Due to the importance of thermo-mechanical processing in the production of these tubes, the dynamic recrystallization (DRX) characteristics of a Cr-Ni super austenitic stainless steel (1.4563) were
    investigated in the present study. This was performed using the hot compression testing method in the temperature range of 950−1150°C and the strain rate of 10-3−10-1 s-1. The initiation and evolution of DRX were examined through microstructural analysis. The results indicated that the recrystallized grain formed a necklace type structure at the prior austenite grain boundaries at higher strain rates. In addition, DRX nucleation occurs by bulging and successive strain induced boundary migration (SIBM).

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    Effect of Varying Carbon Content and Shot Peening upon Fatigue Performance of Prealloyed Sintered Steels
    R. Bidulsky,M. Actis-Grande,M. Kabatova,J. Bidulska
    J. Mater. Sci. Technol., 2009, 25 (05): 607-610. 
    Abstract   HTML   PDF (466KB)

    The aim of the work was to find out how the modification of surface treatment and microstructures affect the fatigue characteristics of the considered sintered materials. Two different systems were prepared: as-sintered and shot peened prealloyed sintered (Astaloy CrL based) steels with addition of 0.5% and 0.7% C. Sintering was carried out in laboratory tube furnace in an atmosphere of pure gases 75%N2+25%H2. The sintering temperature was 1180°C and sintering time was 60 min. Heating and cooling rates were 10°C/min. Fatigue tests were carried out in symmetric plane bending at stress ratio R=−1 with frequency of about 24 Hz. The presented experimental results showed that prealloyed water-atomised steels, with surface modification, exhibit positive effects on the fatigue failure resistance, and for that reason are suitable for high-erformance
    applications.

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    Influence of Surface Treatment on the Corrosion Resistance of Stainless Steel in Simulated Human Body Environment
    Esmaeil Jafariy,Mohammad Jafar Hadianfard
    J. Mater. Sci. Technol., 2009, 25 (05): 611-614. 
    Abstract   HTML   PDF (687KB)

    In the present research, the influence of chromium enrichment by surface treatment on corrosion resistance of type 316L stainless steel in body environment was investigated. For this study, weight loss test during 18 months, cyclic and liner polarization tests before and after surface treatment and metallography by electron
    and light microscopy were used to evaluate the effectiveness of the proposed method. In addition, X-ray photoelectron spectroscopy (XPS) method was used to determine the chromium concentration in the surface layer after surface treatment. Results show that the surface treatment has improved corrosion resistance of the type 316L stainless steel in body environment.

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    Isothermal Growth Kinetics of Ultra-fine Austenite Grains in a Nb-V-Ti Microalloyed Steel
    Shengjie Yao,Linxiu Du,Xianghua Liu,Guodong Wang
    J. Mater. Sci. Technol., 2009, 25 (05): 615-618. 
    Abstract   HTML   PDF (619KB)

    Ultra-fine austenite grains with size of 1~3 μm were prepared in a Nb-V-Ti steel through repetitive treatment of rapid heating and quenching. A model for the growth kinetics of these ultra-fine austenite grains was successfully created through successive 2 processes, and the activation energy Q for growth was estimated to be about 693.2 kJ/mol, which directly shows the inhibition effect of microalloy elements on the growth of ultra-fine austenite grains.

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    Enhancement of GMI Effect in Silicon Steels by Furnace Annealing
    C. Sirisathitkul,P. Jantaratana
    J. Mater. Sci. Technol., 2009, 25 (05): 619-621. 
    Abstract   HTML   PDF (390KB)

    The ratio and sensitivity of giant magnetoimpedance (GMI) in grain oriented silicon steels (Fe-4.5%Si) are improved after furnace annealing in air for 20 min. By annealing at 800°C, the GMI sensitivity rises from 1.29%/Oe to 1.91%/Oe and the ratio increases from 237% to 294% with decreasing characteristic frequency. The results are attributable to an increase in the transverse magnetic permeability during the heat treatment. From simulation by finite element method, the GMI effect can be interpreted as the modification of the current distribution by the applied magnetic field via the transverse permeability. In the case of annealed samples, the larger transverse permeability allows a higher GMI ratio and sensitivity.

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    Sliding Wear Behavior of a Grey Cast Iron Surface Remelted by TIG
    H. Mohamadzadeh,H. Saghafiany,Sh. Kheirandish
    J. Mater. Sci. Technol., 2009, 25 (05): 622-628. 
    Abstract   HTML   PDF (1385KB)

    The sliding wear behavior of a grey cast iron surface remelted by tungsten inert gas (TIG) was studied and compared with the unremelted one in the current work. To evaluate the wear behavior a Pin-on-Disk wear test machine was used. Pins which were prepared from the samples with the remelted layers of different thicknesses
    of 1.2, 1.8, 2.5 and 3 mm were worn on an AISID3 steel counterface having a hardness of 63HRC under the applied loads of 54, 76 and 99 N at a constant sliding velocity of 0.45 m/s. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) techniques were used to characterize worn surface and subsurface and also wear debris obtained from the wear tests under different test conditions. Results showed that surface remelted grey cast iron have better wear properties for all applied normal loads in comparison with unremelted ones. Microscopic studies on the worn surfaces and subsurfaces of samples revealed that dominant wear mechanism for surface remelted samples was mild oxidative, while it was severe for unremelted samples. Increasing remelted layer thickness and then forming grosser microstructure lead to a decline of wear properties, whereas lower thickness of remelted layer with finer microstructure due to having higher cooling rate through remelting process can withstand better against wear.

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    Reduction of Sensitivity to Sintering Temperature for Nd-Fe-B Magnets through Zr and Nb Additions
    Mi Yan,Xigui Cui,Lianqing Yu,Tianyu Ma
    J. Mater. Sci. Technol., 2009, 25 (05): 629-632. 
    Abstract   HTML   PDF (380KB)

    To reduce the sensitivity of grain growth to sintering temperature for improving property consistency of sintered Nd−Fe−B magnets, combined additions of Zr and Nb were investigated. It was found that when Zr content was increased to 0.07 at. pct, abnormal grain growth was effectively hindered even when the sintering temperature reached 1100°C. With combined additions of 0.07 at. pct Zr and 0.07 at. pct Nb, the sensitivity of grain growth to sintering temperature was greatly reduced. The magnets sintered at 1100°C showed higher property consistency than the magnets containing no Zr and Nb. In addition, the magnetic properties of magnets were also improved.

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    Eclipta Alba as Corrosion Pickling Inhibitor on Mild Steel in Hydrochloric Acid
    M. Shyamala,A. Arulanantham
    J. Mater. Sci. Technol., 2009, 25 (05): 633-636. 
    Abstract   HTML   PDF (550KB)

    Due to ease of application, cost effectiveness and environmentally safe, in this study, the corrosion inhibition effect of aqueous extract of Eclipta alba in 1 N hydrochloric acid has been investigated by weight loss, potentiodynamic polarization and impedance methods and the extracts of Eclipta alba were found to be effective corrosion pickling inhibitor. The effect of immersion time and temperature revealed that the extracts of Eclipta alba with an optimum concentration of 8.0% v/v showed maximum inhibition efficiency of 99.6% at 3 h immersion time and 30°C. Arrhenius plots for mild steel immersed in 1 N HCl solution in the absence and presence of optimum concentration (8.0% in v/v) of Eclipta alba extract showed the effect of temperature. Polarization studies indicate that this plant extract acts as a mixed type inhibitor. The adsorption of
    Eclipta alba follows Langmuir adsorption isotherm. The inhibition action may be due to the presence of the Wedelactone and also the alkaloid Ecliptine present in the leaves of Eclipta alba.

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    Evaluation of Oxidation of Ti-Al and Ti-Al-Cr Coatings Arc-ion Plated on Ti-60 High-temperature Titanium Alloy
    Wei Yan,Qingjiang Wang,Jianrong Liu,Shaoqiang Li,Fengjiu Sun
    J. Mater. Sci. Technol., 2009, 25 (05): 637-644. 
    Abstract   HTML   PDF (1262KB)

    High-temperature titanium alloy for aeroengine compressor applications suffers from high-temperature oxidation and environmental corrosion, which prohibits long-term service of this kind alloy at temperatures above 600°C. In an attempt to tackle this problem, Ti-48Al (at. pct) and Ti-48Al-12Cr (at. pct) protective coatings were plated on the substrate of alloy Ti-60 by arc ion plating (AIP) method. Isothermal and cyclic oxidation tests were performed in static air at elevated temperatures. Phase composition, morphology of the coatings and distribution of elements were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results showed that the Ti-48Al coating exhibited good isothermal oxidation resistance during exposure at 800°C, but poorer resistance against oxidation at 900°C. By contrast Ti-48Al-12Cr coating demonstrated excellent isothermal oxidation resistance at both temperatures. Cyclic oxidation tests performed at 800°C indicated that both coatings demonstrated good cyclic oxidation resistance and no spallation of coatings was observed. But at 900°C only Ti-48Al-12Cr coating demonstrated excellent cyclic oxidation resistance.

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    Effects of Yttria Addition on Microstructure, Mechanical Properties, Wear Resistance and Corrosive Wear Resistance of TiNi Alloy
    Hojat Ahmadi,D.Y. Li,Meisam Nouri
    J. Mater. Sci. Technol., 2009, 25 (05): 645-648. 
    Abstract   HTML   PDF (1014KB)

    TiNi alloy has a high resistance to wear and could be an excellent candidate for various tribological applications. But studies show that oxygen active elements can improve properties of some alloys, markedly. Yttrium is one of the oxygen active elements. In this paper, the effects of yttria addition on properties of TiNi have been studied via micro-indentation, hardness, wear and corrosive wear tests. It is demonstrated that by addition of yttria to 5%, TiNi alloy can own improved mechanical properties and resistance to wear and corrosive wear.

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    Effect of Alloying Elements on Microstructure, Martensitic Transformation and Mechanical Properties of Ni-Mn Based Alloys
    K. Alvarez,H.Y. Kim,S. Miyazaki
    J. Mater. Sci. Technol., 2009, 25 (05): 649-654. 
    Abstract   HTML   PDF (815KB)

    The microstructural features, shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal cycling test under various stresses. The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system. The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However, it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn(50-x)-Fex (x=5, 7, 10, 20 at. pct) alloys are presented.

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    Effect of Process Parameters on Tensile Strength of Friction Stir Welded Cast LM6 Aluminium Alloy Joints
    M. Jayaraman,R. Sivasubramanian,V. Balasubramanian
    J. Mater. Sci. Technol., 2009, 25 (05): 655-664. 
    Abstract   HTML   PDF (2327KB)

    This paper reports the effect of friction stir welding (FSW) process parameters on tensile strength of cast LM6 aluminium alloy. Joints were made by using different combinations of tool rotation speed, welding speed and axial force each at four levels. The quality of weld zone was investigated using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone hardness and microstructure. The joint fabricated using a rotational speed of 900 r/min, a welding speed of 75 mm/min and an axial force of 3 kN showed superior tensile strength compared with other joints. The tensile strength and microhardness of the welded joints for the optimum conditions were 166 MPa and 64.8 Hv respectively.

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    Dependence of Amorphous Formation Ability on Intrinsic Parameters in Dy-Gd-Co-Al Alloys
    Lin Luo,Rui Tian,Xueshan Xiao
    J. Mater. Sci. Technol., 2009, 25 (05): 665-668. 
    Abstract   HTML   PDF (666KB)

    A series of Dy(Gd)-based bulk amorphous alloy rods were prepared by water-cooled copper mold method. Thermal stability and structure of Dy-Gd-Co-Al alloys were investigated by differential scanning calorimetry and X-ray diffraction, respectively. The results show that the Dy-Gd-Co-Al alloys have good glass-formation ability, and the Dy31Gd25Co20Al24 alloy can be readily cast into full glassy rods up to 5 mm in diameter. The glass-forming ability of multicomponent alloys was greatly dependent on their chemical interaction and the equivalent bond parameters among atoms such as equivalent electronegativity difference, equivalent atomic size parameter. The Dy (Gd)-based bulk amorphous alloys could be expected as potential functional materials.

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    Morphology Control and Optical Absorption Properties of Ag Nanoparticles by Ion Implantation
    G.X. Cai,F. Ren,X.H. Xiao,L.X. Fan,X.D. Zhou,C.Z. Jiang
    J. Mater. Sci. Technol., 2009, 25 (05): 669-672. 
    Abstract   HTML   PDF (504KB)

    Ion implantation is a powerful method for fabricating nanoparticles in dielectric. For the actual application of nanoparticle composites, a careful control of nanoparticles has to be achieved. In this letter, the size, distribution and morphology of Ag nanoparticles are controlled by controlling the ion current density, ion implantation sequence and ion irradiation dose. Single layer Ag nanoparticles are formed by Ag+ ion implantation at current density of 2.5 μA/cm2. By Ag and Cu ions sequential implantation, the size of single layer Ag nanoparticles increases. While, by Cu and Ag ions sequential implantation, uniform Ag nanoparticles with wide distribution are formed. The morphology of Ag nanoparticles changes to hollow and sandwiched nanoparticles by Cu+ ion irradiation to doses of 3×1016 and 5×1016 ions/cm2. The optical absorption properties of Ag nanoparticles are also tailored by these ways.

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    Liquid Phase Behavior during Elevated Temperature Deformation of the Fine-Grained 5083 Al Alloy
    Honghua Yan,Kaifeng Zhang
    J. Mater. Sci. Technol., 2009, 25 (05): 673-676. 
    Abstract   HTML   PDF (658KB)

    The liquid phase behavior of the fine-grained 5083 Al alloy obtained through thermomechanical process was investigated during the tensile tests in a temperature range of 380−570°C and strain rate range of 4.17×10-4−1.0Χ10-2 s-1. The maximum elongation 530% of the fine-grained 5083 Al alloy was obtained at 550°C and 4.17×10-4 s-1. Fracture analysis by scanning electron microscopy (SEM) indicated that the formation of filament (formed by liquid phase) was greatly affected by the tensile temperature and strain rate. The results also showed that the optimum morphology of formed filament was obtained at 550°C and a strain rate of 4.17×10-4 s-1. The effect of liquid phase on superplastic deformation of the alloy was further discussed.

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    Analysis of the Vertical and Lateral Interactions in a Multisheet Array of InAs/GaAs Quantum Dots
    Hui She,Biao Wang
    J. Mater. Sci. Technol., 2009, 25 (05): 677-680. 
    Abstract   HTML   PDF (666KB)

    The vertical and lateral interactions in a multisheet array of InAs/GaAs quantum dots are analyzed by finite element method (FEM). It is shown that due to the effects of vertical interaction, nucleation prefers to happen above buried quantum dots (QDs). Meanwhile, the effects of lateral interaction adjust the spacing of lateral neighboring QDs. The vertical coupling becomes strong with deceasing GaAs spacer height and increasing number of buried layers, while the lateral coupling becomes strong with increasing InAs wetting layer thickness. The phenomenon that, after successive layers, the spacing and size of QDs islands become progressively more uniform is explained according to the minimum potential energy theory.

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    Effect of Sample Configuration on Droplet-Particles of TiN Films
    Yanhui Zhao,Guoqiang Lin,Jinquan Xiao,Chuang Dong,Lishi Wen
    J. Mater. Sci. Technol., 2009, 25 (05): 681-686. 
    Abstract   HTML   PDF (552KB)

    Orthogonal experiments are used to design the pulsed bias related parameters, including bias magnitude, duty cycle and pulse frequency, during arc ion deposition of TiN films on stainless steel substrates in the case of samples placing normal to the plasma flux. The effect of these parameters on the amount and the size distribution of droplet-particles are investigated, and the results have provided sufficient evidence for the physical model, in which particles reduction is due to the case that the particles are negatively charged and repulsed from negative pulse electric field. The effect of sample configuration on amount and size distribution of the particles are analyzed. The results of the amount and size distribution of the particles are compared to those in the case of samples placing parallel to the plasma flux.

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    Microstructure and Wear Behavior of FeBSiNbCr Metallic Glass Coatings
    Jiangbo Cheng,Xiubing Liang,Binshi Xu,Yixiong Wu
    J. Mater. Sci. Technol., 2009, 25 (05): 687-690. 
    Abstract   HTML   PDF (399KB)

    In this paper, FeBSiNbCr metallic glass coatings were prepared onto AISI 1045 steel substrate by using wire arc spraying process. The phase and structure of the coating were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning election microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX). The microstructure of the coating consists of full amorphous phase. The coating has high hardness and low porosity. Full density and little oxides are detected in the coating. The mechanical properties, especially wear resistance, were investigated. The relationship between wear behavior and structure of the coatings were analyzed in detail. The main failure mechanism of the metallic glass coating is brittle breaking and fracture. The results indicate that FeBSiNbCr metallic glass coating has excellent resistance to abrasive wear.

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    Effects of Homo-bu®er Layer on Properties of Sputter-deposited ZnO Films
    Jian Huang,Linjun Wang,Run Xu,Weimin Shi,Yiben Xia
    J. Mater. Sci. Technol., 2009, 25 (05): 691-694. 
    Abstract   HTML   PDF (438KB)

    Two-step growth regimes were applied to realize a homoepitaxial growth of ZnO films on freestanding diamond substrates by radio-frequency (RF) reactive magnetron sputtering method. ZnO buffer layers were deposited on freestanding diamond substrates at a low sputtering power of 50 W, and then ZnO main layers were prepared
    on this buffer layer at a high sputtering power of 150 W. For comparison, a sample was also deposited directly on freestanding diamond substrate at a power of 150 W. The effects of ZnO buffer layers on the structural, optical, electrical and morphological properties of the ZnO main layer were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, semiconductor characterization system and atomic force microscopy (AFM) respectively. The experimental results suggested that homo-buffer layer was helpful to improve the crystalline quality of ZnO/diamond heteroepitaxial films.

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    Preparation, Microstructure and Properties of NiO-Cr2O3-TiO2 Infrared Radiation Coating
    Wu Chen,Weiping Ye,Xudong Cheng,Wei Duan,Fang Mao,Deliang Li
    J. Mater. Sci. Technol., 2009, 25 (05): 695-698. 
    Abstract   HTML   PDF (527KB)

    The spherical agglomerated particles were fabricated by spray drying with the powders of NiO, Cr2O3 and TiO2. Plasma spray power, which has good property of flowability, was acquired by heat treatment from the particles at 1200°C in the reducing atmosphere. Dark and uniform coating of More than 50 μm thick was deposited on the copper sheet substrate by plasma spraying. It is found that the infrared normal total emissivity of the coating is up to 0.91 at 600°C by infrared radiation testing. The X-ray diffraction analysis shows that the formation of (Cr0:88Ti0:12)2O3 and spinel structural NiCr2O4 in the coating is the main reason for high efficient infrared radiation, and the phase structure and performance of coating is favorable under the thermal cycle between room temperature and 600±C.

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    Effects of Interface and Grain Boundary on the Electrical Resistivity of Cu/Ta Multilayers
    M. Wang,B. Zhang,G.P. Zhang,Q.Y. Yu,C.S. Liu
    J. Mater. Sci. Technol., 2009, 25 (05): 699-702. 
    Abstract   HTML   PDF (376KB)

    The electrical resistivity of Cu/Ta multilayers deposited by radio-frequency magnetron sputtering on a polyimide substrate was investigated as a function of monolayer thickness. It is found that the resistivity of the multilayer increases with decreasing monolayer thickness from 500 nm to 10 nm. Two significant effects of layer interface
    scattering and grain boundary scattering were identified to dominate electronic transportation behavior in the Cu/Ta multilayers at different length scales. The electrical resistivity of the multilayer with monolayer thickness ranging from nanometer to submicron scales can be well described by a newly-proposed Fuchs-Sandheimair
    (F-S) and Mayadas-Shatzkes (M-S) combined model.

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    Optimization of Polishing Parameters with Taguchi Method for LBO Crystal in CMP
    Jun Li,Yongwei Zhu,Dunwen Zuo,Yong Zhu,Chuangtian Chen
    J. Mater. Sci. Technol., 2009, 25 (05): 703-707. 
    Abstract   HTML   PDF (269KB)

    Chemical mechanical polishing (CMP) was used to polish Lithium triborate (LiB3O5 or LBO) crystal. Taguchi method was applied for optimization of the polishing parameters. Material removal rate (MRR) and surface roughness are considered as criteria for the optimization. The polishing pressure, the abrasive concentration
    and the table velocity are important parameters which in°uence MRR and surface roughness in CMP of LBO crystal. Experiment results indicate that for MRR the polishing pressure is the most significant polishing parameter followed by table velocity; while for the surface roughness, the abrasive concentration is the most important one. For high MRR in CMP of LBO crystal the optimal conditions are: pressure 620 g/cm2, concentration 5.0 wt pct, and velocity 60 r/min, respectively. For the best surface roughness the optimal conditions are: pressure 416 g/cm2, concentration 5.0 wt pct, and velocity 40 r/min, respectively. The contributions of individual parameters for MRR and surface roughness were obtained.

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    Multi-objective Optimization of Co-cured Composite Laminates with Embedded Viscoelastic Damping Layer
    Lijian Pan,Boming Zhang,Fuhong Dai
    J. Mater. Sci. Technol., 2009, 25 (05): 708-712. 
    Abstract   HTML   PDF (427KB)

    Presented herein is a methodology for the multi-objective optimization of damping and bending stiffness of co-coured composite laminates with embedded viscoelastic damping layer. The embedded viscoelastic damping layer is perforated with a series of small holes, and the ratio of the perforation area to the total damping area is the design variable of the methodology. The multi-objective optimization is converted into a single-objective problem by an evaluation function which is a liner weigh sum of the two sub-objective functions. The proposed methodology was carried out to determine the optimal perforation area ratios of two viscoelstic layers with different perforation distance embedded in two composite plates. Both the optimal perforation area ratios are approximate to 2.2%. However, the objective value of the plate with greater perforation distance in embedded viscoelatic layer is much greater.

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    Study of Debond Fracture Toughness of Sandwich Composites with Metal Foam Core
    Xinzhu Wang,Linzhi Wu,Shixun Wang
    J. Mater. Sci. Technol., 2009, 25 (05): 713-716. 
    Abstract   HTML   PDF (441KB)

    Two types of experiments were designed and performed to evaluate the adhesive bond in metal foam composite sandwich structures. The tensile bond strength of face/core was determined through the flatwise tensile test (FWT). The test results show that the interfacial peel strength is lower than the interlaminar peel strength in FWT test. The mode I interfacial fracture toughness (GIC) of sandwich structures containing a pre-crack on the upper face/core interface is determined by modified cracked sandwich beam (MCSB) experiment. It is found that the crack propagates unsynchronously on the two side of the specimen and the propagation of interfacial debonding always stays on the face/core interface during the MCSB tests. In order to simulate the failure of metal foam composite sandwich structures, a computational model based on the Tsai-Hill failure
    criterion and cohesive zone model is used. By comparing with experiment results, it can be concluded that the computational model can validly simulate the interfacial failure of metal foam composite sandwich structures with reasonable accuracy

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    Preparation of Al3Sc Intermetallic Compound by FFC Method
    Xianjie Liao,Hongwei Xie,Yuchun Zhaiy,Yi Zhang
    J. Mater. Sci. Technol., 2009, 25 (05): 717-720. 
    Abstract   HTML   PDF (554KB)

    The FFC Cambridge process is a direct electrodeoxidation process used to reduce metal oxides for metals or alloys in molten salts. Al-Sc compound oxides are used as a precursor which formed upon blending and sintering Al2O3, Sc2O3 and Al powders and are successfully reduced by using the FFC Cambridge process at 973 K with a constant cell voltage of −3.2 V. This method is applied to the preparation of fine Al3Sc particles, which can give another new view for aluminum industry.

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