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      20 September 2011, Volume 0 Issue 9 Previous Issue    Next Issue
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    Thermodynamic Calculation and Experimental Analysis on Undissolved Phases of 30Cr3Si2Mn2NiNb Steel
    LU Yan, WANG Jun-hua, SU Jie, DING Ya-li, YANG Zhuo-yue, XIE Gang
    2011, 0 (9): 1-5,19.  
    Abstract ( 301 ( PDF (1228KB)( 190 Citation
    Evolution of equilibrium phases and non-equilibrium phases in 30Cr3Si2Mn2NiNb steel during austenitizing was simulated via Thermo-Calc thermodynamic software.Effect of C,Mo,Nb and V on undissolved phases in steel was studied.Experimental analysis was carried out by SEM and XRD on microstructure of as-quenched 30Cr3Si2Mn2NiNb steel.Results show that there are Mo-enriched M6C and Nb-enriched MC phases in steel after austenitizing below 950℃,and MC phases are dramatically reduced while M6C phases are almostly dissolved above 950℃.The proper austenitizing temperature of 30Cr3Si2Mn2NiNb steel is 950-1000℃.The results of calculation indicate that C,Nb retard dissolution of MC phase while V,Mo promot the dissolution.
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    Influence of Stiffener on High Precision Calculation Using Big Grid Composite Element
    QIAO Sheng-jun, WANG Fu-sheng, ZHAO Bin, YUE Zhu-feng
    2011, 0 (9): 6-13,28.  
    Abstract ( 305 ( PDF (837KB)( 341 Citation
    The present study aimed at high precision calculation of double curved composite by using programming element,which was an extension of 8-node shell element theory.It is found that stiffener has little influence on precision of calculation.In the view of precision and efficiency,this programming element can be applied to finite element analysis with or without stiffener,providing a quick solution to finite element analysis of large engineering structure.
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    Fabrication of Bi4Ti3O12 Functional Ceramic Film by Self-assembled Monolayers Technique
    XIA Ao, HUANG Jian-feng, TAN Guo-qiang, LIU Dan
    2011, 0 (9): 14-19.  
    Abstract ( 377 ( PDF (1870KB)( 270 Citation
    Bi4Ti3O12 film was prepared on the glass substrate by the self-assembled monolayer(SAM) technique with Bi(NO3)3 and (NH4)2TiF6 as the raw material and octadecyltrichlorosilane(OTS) as the template.Hydrophilic characteristic measure of glass wafers and photographs of atomic force microscopy(AFM) indicate that the hydrophobe substrate changes into hydrophile by UV irradiation,and a modification of OTS-SAM is realized by UV light.Effects of pH values,deposition conditions and calcining temperatures on the phase composition,the microstructure and surface morphology of Bi4Ti3O12 film were analyzed by XRD and SEM.The results show that the Bi4Ti3O12 film is prepared by the self-assembled monolayer technique,and the films are uniform and dense with precursor pH value of 1.30,deposition condition of 60℃ for 6h.The suitable calcining temperature for Bi4Ti3O12 film is 600℃.
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    Microstructure and Mechanical Property Analysis on Double-sided Friction Stir Welding Joints of 60mm 6061-T6 Aluminum Alloy Plate
    HE Di-qiu, LUO Wei, WU Hong-guang
    2011, 0 (9): 20-24.  
    Abstract ( 453 ( PDF (1207KB)( 700 Citation
    Double-sided friction stir welding was applied to connection of 6061-T6 aluminum alloy plates,the microstructure and mechanical properties of the joints were investigated.The results show that the microstructure undergoes different changes in the through-thickness direction,the tensile strength of the joint reaches 218MPa,70% that of the parent material.The re-solution and over-aging of the strengthening phases caused by welding thermal cycle have a great effect on the strength degradation,and the thermal mechanical affected zone of the advancing side is the welding weakness.
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    Effects of HIP Treatment Parameters on Microstructure of ZTC4 Casting Titanium Alloy
    YANG Wei-guang, ZHAO Jia-qi, NAN Hai, WU Guo-qing
    2011, 0 (9): 25-28.  
    Abstract ( 446 ( PDF (675KB)( 207 Citation
    Quantitative metallography technique was used to investigate the effects of hot isostatic pressing(HIP) treatment parameters on microstructure of ZTC4 casting titanium alloy.The results show that the β grain size and α lamella thickness of ZTC4 increase obviously after HIP treatment relative to as-cast microstructure of ZTC4 alloy.With the increase of temperature and holding time of HIP treatment,β grain size and α lamella thickness increase in a near linear manner with a range of 40-70μm and 0.6-1μm respectively.However,with the increase of pressure of HIP treatment,the change of β grain size and α lamella thickness occurs from increase to decrease.Compared with as-cast microstructure,the growth rates of β grain size and α lamella thickness of ZTC4 titanium alloys after HIP treatment are 12%-25% and 57%-100% respectively.
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    Effects of Adding 0.05%(La+Ce) on Intermetallic Compounds at Sn-X-Cu-Ni /Cu Interface
    CHEN Hai-yan, JIE Xiao-hua, ZHANG Hai-yan, GUO Li
    2011, 0 (9): 29-32,38.  
    Abstract ( 423 ( PDF (772KB)( 684 Citation
    The microstructure evolution and the behavior of the formation and growth of intermetallic compound(IMC) layer at the interface between Sn-4.1X-1.5Cu-Ni solder and Cu substrate after isothermal aging were studied.The results show that the thickness of IMC layers in Sn-4.1X-1.5Cu-Ni/Cu system and Sn-4.1X-1.5Cu-Ni-0.05(La+Ce)/Cu system increases with the increase of the aging time,and their growth is mainly controlled by diffusion mechanism.The addition of 0.05%(mass fraction)(La+Ce) into the Sn-X-Cu-Ni solder alloy effectively inhibits the formation and growth of IMC during the isothermal aging,which develops solder alloy with a high reliability.Intermetallic growth rate constant for Sn-4.1X-1.5Cu-Ni/Cu and Sn-4.1X-1.5Cu-Ni-0.05(La +Ce)/Cu is 2.95×10-17m2/s and 2.51×10-17m2/s,respectively.
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    Preparation of Thermal Insulation Block by Slip Casting and Drying at Ambient Pressure and Room Temperature
    ZHANG Ming-can, ZENG Ren-jie
    2011, 0 (9): 33-38.  
    Abstract ( 362 ( PDF (612KB)( 416 Citation
    A thermal insulation block with suitable compressive strength was prepared.Silica aerogel was used as a matrix,E-glass fiber as a framework,titanium dioxide as an opacifier.Compressive strength(R),thermal conductivity(λ) and volume resistivity(ρ) at room temperature(25℃) were measured,respectively.Results show that the aqueous slurry is well dispersed when pH=8-9;the sample heated at 730℃ for 0.5h has a lower density(D) of 151kg·m-3 compared with The Standard of American Society for Testing of Materials(ASTM C533—85),and the same R value 0.41MPa as the standard.At ambient pressure,the sample has thermal conductivity(λn) of 0.036W·m-1·K-1. at room temperature and 0.061W·m-1·K-1. at 480℃,respectively.The values are lower or much lower than those of traditional thermal insulation blocks,respectively.The preparation processing of thermal insulation block was investigated systematically.The white Portland cement clinker was creactively used as a binder,and the block was made by slip casting and then being dried at ambient pressure and room temperature.Both the raw materials and the sample are non-toxic.This project has good industrialization prospects owing to its processing simple and low cost.
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    Coupled Erosive Behavior of Naphthenic Acid and Sulfur at High Temperatures
    HUANG Ben-sheng, SANG Dong-heng, JIANG Zhong-ying, LIU Qing-you
    2011, 0 (9): 39-44,49.  
    Abstract ( 336 ( PDF (1091KB)( 185 Citation
    Naphthenic acid and sulfur exist simultaneously during the refining process,and so its coupled coordination corrosion affects the manufacture of oil refining enterprises.By simulating the corrosion of oil field,the coupled coordinated corrosion research of naphthenic acid and sulfur was carried out in high-temperature reactor,and then the corrosion products were analyzed by EDS and XRD.The results show that at high temperature,in sulfur only medium,the corrosion rate of two kinds of steels increases firstly and then decreases with the increase of mass fraction of sulfur;in the condition of coupled coordinated corrosion,when sulfur content is 1%(mass fraction),with the increase of acid value the corrosion rate of Q235 increases all the way,and the increase tendency of corrosion becomes bigger when acid value is over 9mgKOH·g-1;while the corrosion rate of 316 steel increases firstly,decreases secondly and then increases,so 316 steel has two critical acid value of 9mgKOH·g-1. and 12mgKOH·g-1;when acid value is 9mgKOH·g-1,with the increase of mass fraction of sulfur the corrosion rate of 316 increases firstly and then decreases,while Q235 increases all the way;after analyzed the corrosion films,found that the corrosion film of Q235 steel has crumbly Fe7S8;sulfur content,acid value and temperature affect the corrosion membrane morphology of coupled coordinated corrosion.
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    Influence of Phytic Acid Concentration on Corrosion Resistance of Phytic Acid Conversion Coating on AZ31B Magnesium Alloy
    GAO Huan-fang, ZHANG Sheng-tao, ZHAO Bo, LIU Yi-feng, ZOU Yong
    2011, 0 (9): 45-49.  
    Abstract ( 306 ( PDF (702KB)( 286 Citation
    The phytic acid conversion coatings on AZ31B magnesium alloy were formed in different phytic acid concentrations and the corrosion resistance of the conversion samples was studied by hydrogen evolution method and Tafel.The morphology,composition and functional groups were investigated by SEM,EDS and FTIR,respectively.The results indicate that the concentration of phytic acid has obvious influence on the corrosion resistance of the conversion samples,the conversion sample formed under C=4.0g·L-1. has the best corrosion resistance,the current density decreases about two orders than that of the untreated sample.The main elements of the coating are Mg,Al,Zn,O and P,the functional groups are PO43-,HPO42- and OH-.The conversion coating also has few cracks,and the thin coating is formed on the crack.
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    Corrosion Behaviour of Chromium Plating on A100 Steel in Marine Environment
    TANG Zhi-hui, LIU Peng, WANG Xu-dong, LIU Ming, SUN Zhi-hua
    2011, 0 (9): 50-55.  
    Abstract ( 455 ( PDF (1442KB)( 204 Citation
    The corrosion behaviour of the chromium plating on A100 steel was investigated under the outdoor exposure environments in Hainan.The surface and transverse micrographs of the corroded plating were observed by scanning electron microscope.The features for the various corrosion stages were characterized by the electrochemical impedance spectroscopy,and the effect of corrosion on the mechanical properties was also discussed.The results indicate that the microcrack on the plating surface is a main influencing factor at the initial and the propagating stages of corrosion,and the effect of corrosion on the mechanical properties is serious,the corrosion leads to tensile strength decrease and make the mechanical properties of the mechanical test specimens present a brittle fracture trend.
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    Influence of SRB on Corrosion Behaviour of AZ91. Magnesium Alloy in Two Kinds of Culture Media
    FANG Shi-jie, LIU Yao-hui, QIAO Jian, ZHANG Wei
    2011, 0 (9): 56-61,67.  
    Abstract ( 335 ( PDF (1237KB)( 204 Citation
    Soaking method,SEM and EDS analyses were applied to evaluate the influence and mechanism of sulfate-reducing bacteria(SRB) for the corrosion of AZ91. magnesium alloy in two kinds of culture media.The results show that,SRB can adhere and grow on the surface of AZ91,and then form a biofilm.The biofilm inhibits the corrosion of AZ91. at(30±1)℃.The biofilm formed in the culture medium with(NH4)2Fe(SO4)·6H2O and C6H8O6 is loose,and plays a weak protective role for the matrix.Furthermore,Fe2+ ions in(NH4)2Fe(SO4)·6H2O improve the metabolism of SRB significantly,however,they can form the deposition of FeS,which accelerates the corrosion of AZ91.
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    Effects of Cu on Sea Water Corrosion Resistance of Low Alloy Steels
    CAO Guo-liang, LI Guo-ming, CHEN Shan, CHANG Wan-shun, CHEN Xue-qun
    2011, 0 (9): 62-67.  
    Abstract ( 327 ( PDF (1157KB)( 335 Citation
    In order to understand the effect of Cu on sea water corrosion resistance of low alloy steels,two Cu-containing low alloy steels and carbon steels were selected.Their general and pitting corrosion resistance was evaluated by indoor interval hanging plate tests,marine tide hanging plate tests and simulating occluded corrosion cell tests.The composition of inclusions,corrosive feature and characteristics of rust layers were studied by scanning electron microscopy(SEM),energy dispersive analysis of X-ray(EDAX),electron probe micro-analyzer(EPMA) and X-ray diffraction(XRD).The results indicate that general corrosion resistance and pitting corrosion resistance are enhanced by addition of Cu.In macro cathodic region,addition of Cu facilitates formation of α-FeOOH,and then improves protective ability of rust layer for matrix.In acidified pits,the insoluble salt that Cu formed can repair and fill the slots and holes in rust layers,which are effective in improving resistance to pitting corrosion.
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    Early Fault Inspection of Wet Stream Generator Tubes Based on Metal Magnetic Memory
    YAN Ting-jun, ZHANG Jie-dong, FENG Guo-dong, CHEN Jian-fei
    2011, 0 (9): 68-71.  
    Abstract ( 322 ( PDF (582KB)( 220 Citation
    Tensile test and fatigue test on wet steam generator 20G tubes were carried out and the metal magnetic memory(MMM) signals were detected.Though the analysis of MMM signals from different loading stages and different fatigue cycles,the variation characteristic of the MMM signals was obtained and a novel quantitative evaluation method of the early failure by MMM technology was proposed and applied in oilfield on-site test finally.The test results show that MMM method can effectively locate the stress concentration zone(SCZ).The magnetic gradient indicates the damage severity of the investigated zone of the tube.If the magnetic gradient is above 12A·(m·mm)-1,the zone interested is damaged seriously.
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    Properties of Hollow Phenolic Fibers with Different Structure in Carbonized Process
    ZHANG Dong-qing, SHI Jing-li, GUO Quan-gui, SONG Yan, LIU Lang
    2011, 0 (9): 72-76.  
    Abstract ( 309 ( PDF (983KB)( 224 Citation
    Hollow phenolic fibers(PFs) with different hollowness and different diameters structure were carbonized in N2 atmosphere.The mass,diameter,section morphologies and mechanical properties were studied at different carbonization temperatures.All these fibers were characterized by the optics-microcope,SEM and tensile strength.The results show that diameter and mass decrease with heat-treatment temperature increase,the morphologies of hollow PFs are retained through carbonized process,and mechanical properties change with the reaction of decomposing and polymerizing.
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    Preparation and Magnetic Property of Ni-doped Chrysotile Nanotubes
    MA Guo-hua, PENG Tong-jiang, WU Wei-dong, LIU Hai-feng, LI Ming
    2011, 0 (9): 77-81.  
    Abstract ( 354 ( PDF (856KB)( 239 Citation
    Ni-doped chrysotile nanotubes were synthesized by hydrothermal method.The relations among morphology,structure,magnetic and Ni2+ content were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),Fourier transform infrared spectroscopy(FTIR) and magnetic measurement techniques.The results show that the outer and inner diameter of synthesized nanotubes are 30-40nm and 6-7nm.With an increase of Ni2+ content,the cell-parameter(b0) of synthesized samples can be varied from 0.9190nm to 0.9261nm.The prepared Ni-doped samples have room-temperature ferromagnetic behaviors.With an increase of Ni2+ content,the saturated magnetization of samples varies from 2.2×10-4 A·m2·kg-1. to 4.7×10-4A·m2·kg-1. under the same applied field.Partial Ni2+ ions form noncrystalline nickel oxide in the synthesized nanotubes and the nickel oxide has paramagnetic behavior.
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    Structure and Flexural Behavior of C/Mullite/Si-C-N Composite
    LU Guo-feng, QIAO Sheng-ru, JIAO Geng-sheng, XU Hao-long
    2011, 0 (9): 82-86,91.  
    Abstract ( 284 ( PDF (1108KB)( 193 Citation
    Carbon fiber reinforced Si-C-N matrix composite with a mullite interlayer(C/Mullite/Si-C-N) was fabricated.The flexural behavior of the composite was investigated at RT,1300℃ and 1600℃,respectively.The structure and fracture of the composite were observed by using scanning electron microscope(SEM) and transmission electron microscope(TEM) techniques.The results indicate that the fracture of the composite appears obvious characteristics of brittle fracture at RT and 1300℃,and features of gliding fracture at 1600℃.At 1600℃,both the flexural strength and the modulus show a remarkable decrease.The use of mullite interlayer makes the strength of C/Mullite/Si-C-N obviously lower than that of the C/Si-C-N with pyrolytic carbon interlayer.
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    Research Progress in Influence of Twins on Mechanical and Electrical Properties of Cu
    CHEN Xian-hua
    2011, 0 (9): 87-91.  
    Abstract ( 296 ( PDF (319KB)( 659 Citation
    Much attention is paid on the twins in pure Cu.The classification and crystallographic structure of twins are introduced.The effect of twins on strength,ductility,strain hardening,strain rate sensitivity,plastic deformation mechanism and electrical resistivity(or conductivity) is summarized,and the mechanisms underlying these phenomena are discussed.At the same time,it is discussed what should be studied further in the Cu with twins.It is eventually pointed out that introducing high density of twins in grains by using proper preparation technique could obtain high strength,improved ductility as well as good conductivity,and it should be also a noteworthy research direction for developing high performance engineering Cu and its alloys in the future.
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    Development in Research on Metal Diffusion Barrier of TBCs
    CAI Yan, YI Jun, LU Feng, TAO Chun-hu
    2011, 0 (9): 92-96.  
    Abstract ( 399 ( PDF (320KB)( 477 Citation
    The need for diffusion barriers between the thermal barrier coatings(TBCs) and nickel base superalloy is introduced.The design and development of diffusion barriers are reviewed.It emphasizes to discuss the performance of these diffusion barriers such as noble metal,rare metal,compound-forming metal and ceramic diffusion barrier etc.Meanwhile,the deposition technology,inhibition effect and application field of the diffusion barrier are also described and compared.It is pointed out that the multi-layer diffusion barriers have great potential for novel TBCs with long service life.Finally,the problems about the adhesion of diffusion barrier between TBCs and substrate are brought forward.
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