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      20 July 2011, Volume 0 Issue 7 Previous Issue    Next Issue
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    Axial Compression Stability Analysis of Composite Circular Grid Structure with Outer Skin
    LIAO Ying-qiang, LIU Yong-qiong
    2011, 0 (7): 1-5,48.  
    Abstract ( 313 ( PDF (681KB)( 136 Citation
    In order to achieve high load-carrying efficiency for fiber winding composite circular grid structure with outer skin,axial compression stability is analyzed using FEM.Parameter design program is finished using the APDL language of ANSYS.Changing law of load-to-mass ratio for circular grid structure with outer skin which is attached to helical stiffener winding angle,stiffener cross area,stiffener aspect ratio,helical stiffener couples and hoop stiffener strips has been researched utilizing the parameter design program.Axial compression experiment of specific dimension grid structure is carried out on the INSTRON1346 material fatigue strength test machine.It is shown that axial compression load-carrying capacity can be predicted using FEM;when helical stiffener winding angle is from a value between 0 degree and 40 degree,load-carrying efficiency of circular grid structure is more higher;better value for stiffener aspect ratio is in the range of 0.9-1.3.
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    Fabrication for the Composed Electrode of Solid Oxide Fuel Cells by Atmospheric and Suspension Plasma Spray
    WANG Gui-lan, XIONG Fan, RUI Dao-man, ZHANG Hai-ou
    2011, 0 (7): 6-9.  
    Abstract ( 407 ( PDF (986KB)( 213 Citation
    A method for fabricating composed electrode of solid oxide fuel cell(SOFC) on silicon substrate by atmospheric and suspension plasma spray is presented.Anode and cathode layers were deposited by atmospheric plasma spraying(APS) using dry powder feedstock;Electrolyte layer was deposited by suspension plasma spraying(SPS) using mechanical injection.Suspension penetration within the plasma jet was monitored by a CCD camera and the best injection pressure was 0.25MPa by the characteristics analysis of the CCD pictures.The composed electrode layers were characterized in terms of microstructure and composition by SEM and EDAX.Experimental results showed that spray distance was the most important parameter,which influenced electrolyte microstructure,deposition efficiency and porosity;suspension plasma spray could fabricate thin(25μm),fine grain(2-4μm) and dense(porosity of 2.15%) electrolyte layer of SOFC.
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    Study on Preparation and Mechanism of Reduction and Growth of Ultrafine Nickel Powders
    ZHAN Jing, YUE Jian-feng, ZHANG Chuan-fu
    2011, 0 (7): 10-14,65.  
    Abstract ( 353 ( PDF (1412KB)( 224 Citation
    Ultrafine nickel powders were prepared in nickel sulfate aqueous solution by controlling reaction conditions of liquid-phase reduction method using hydrazine as reducing agent.Mechanism of reduction and growth of ultrafine nickel powder was also discussed.The effect of process parameters on reduction reaction was analyzed through the experiments.Ultrafine nickel powders were characterized by the X-ray diffraction(XRD),scanning electron microscopy(SEM) and specific surface area measurement.The results showed that the nucleation and growth of ultrafine nickel powder were independent.The release of nickel ions and the supersaturation,which can make it possible to achieve very short nucleation process,high nucleation rate and relative slow nuclei growth rate,were regulated by temperature,concentration of Ni2+ and pH value.In addition,the surfactant can inhibit the aggregation of powders and make it easy to prepare monodisperse ultrafine nickel powder.The ultrafine spherical nickel powders of high purity were synthesised in a high conversion rate by a liquid-phase reduction method using hydrazine as reducing agent,the obtained powders have small particle size,large specific surface area and good dispersion.
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    Analytic Prediction on the Curing Degree of Adhesive Bonded Automobile Aluminum Joint
    LU Zhi-guo, LIN Jian-ping, ZHANG Bao-wen
    2011, 0 (7): 15-19.  
    Abstract ( 363 ( PDF (427KB)( 148 Citation
    To predict the curing degree of adhesive bonded automobile aluminum joint,the heat transferring process of the joint within the curing process was experimentally analyzed;Based on the experimental results,the inner heat released by adhesive is neglected;the temperature distribution of the joint is considered to be uniform.According to the joint energy balance,the temperature variation of the joint has been studied,following which the analytic curing degree prediction model of joint is established,and then verified through experiments.Finally,the effects of curing parameters and substrate thickness on the curing degree were discussed.It has been found that increasing cuing temperature can significantly improve the curing rate of the joint while increasing the preheat temperature or decreasing the adherend thickness can not improve the curing rate of the joint,but make the curing of adhesive start earlier.It has also been found that the effect of preheat temperature can be more pronounced at a great adherend thickness.
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    Effect of Cold-deformation and Mid-temperature Treatment on Phase Transformation of TiNiCr Shape Memory Alloys
    SI Nai-chao, ZHENG Li-bo, SI Song-hai, LI Lei, ZHAI Yu-jing
    2011, 0 (7): 20-25.  
    Abstract ( 546 ( PDF (826KB)( 153 Citation
    The effect of cold-deformation and mid-temperature treatment on the phase transformation behaviors of TiNiCr SMA(shape memory alloys) have been comparatively investigated.The effect of different cold-deformation and mid-temperature treatment on the DSC curve and phase transformation point of TiNiCr shape memory alloys have been researched by differential scanning calorimeter(DSC) and observation of metallographic microstructure photographs.The results show that martensitic transition temperature Ms would rise as the cold-deformation increased until that the cold-deformation increased more than 15%,then the Ms is reducing with the the cold-deformation increasing.As and Af reached the peak point when the cold-deformation is up to 15%.The martensitic transformation temperature can be significantly improved by heat-treatment which made phase transformation easily.The Ms increasing rate is remarkably increased after heating at 460℃and decreased with mid-temperature treatment increasing.Under the heat treatment temperature of 400℃the Ms and Mf will decrease more remarkably as the more time is keeping.The thermal hysteresis As-Ms is not affected by the time of mid-temperature treatment.
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    Research on Annealing Institution of the New Al-Mn-Mg Alloy Pipe
    MO Jian-xin, PAN Qing-lin, LI Jian-xiang, YANG Zhi-bing, FAN Xi
    2011, 0 (7): 26-30,55.  
    Abstract ( 334 ( PDF (2140KB)( 96 Citation
    Influence of annealing on the microstructure and mechanical properties of the Al-Mn-Mg alloy was studied by mechanical properties test,OM and TEM observation.The results show that after annealed below 300℃,alloy happens only with recovery,and annealed at 300-400℃the recrystallization happens now.A large amount of manganiferous particles precipitate during annealing at 400℃,which play the role of dispersion-strengthened.After annealed at 400℃for 1h,alloy has fine equiaxial grain structure with full recrystallization and also posses better mechanical properties.
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    Preparation and Performance of Carbon-coated Copper Nanoparticles
    CHEN Jin, ZHANG Hai-yan, LIU Xiao-ping, LI Li-ping
    2011, 0 (7): 31-33,89.  
    Abstract ( 422 ( PDF (701KB)( 241 Citation
    Carbon coated copper nanoparticles were prepared by carbon discharge method.The structure,size distribution and phase composition of the particles were investigated by TEM,XRD and DSC.Meanwhile,The conductivity of carbon-coated copper nanoparticles were measured.Results indicate that carbon coated copper nanoparticles were core-shell structure for the copper core inside,the multi carbon layer outside,around the copper core is graphite-like carbon and far away from the copper core is amorphous carbon.While carbon-coated copper nanoparticles at room temperature and high temperatures have shown good oxidation resistance;The conductivity of carbon-coated copper nanoparticles with metal content increases and when the copper content is 80% the conductivity jump.
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    Study of Water Vapor Corrosion at 1300℃of Si/3Al2O3·2SiO2+BSAS/Yb2SiO5 Environmental Barrier Coatings
    HE Shi-mei, MU Ren-de, XU Zhen-hua, HE Li-min, HUANG Guang-hong
    2011, 0 (7): 34-38,43.  
    Abstract ( 496 ( PDF (859KB)( 210 Citation
    A Si bond coat had been deposited on a Cf/SiC specimen by electron beam physical vapor deposition(EB-PVD),and then a mixed layer of mullite and BSAS and a Yb2SiO5 top coat were sprayed by plasma spraying(PS).The water vapor corrosion behavior was tested under the conditions of 0.54m/s,1.013×105Pa and 1300℃.The results indicate that the loss of mass was observed after 175h exposure under experiment conditions.The formation and volatilization of Yb(OH)3 and Si(OH)4 can be accountable for mass loss of those specimens.The combination of outward diffusions of Ba,Sr and Al in middle coating and inward diffusions of Yb in Yb2SiO5 coating,and residual stresses existed in EBC lead to the failure of EBC.
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    Fabrication and Evaluation of Electro-brush Plating and Laser Cladding Duplex Coating on the Surface of Cast Iron
    DONG Shi-yun, ZHANG Xiao-dong, WANG Zhi-jian, XU Bin-shi, LI Qing-fen
    2011, 0 (7): 39-43.  
    Abstract ( 448 ( PDF (1500KB)( 224 Citation
    In order to solve the laser cladding crack problem of cast iron parts,electro-brush plating and laser cladding duplex remanufacturing was employed.The microstructure,hardness,friction and wear performance of the duplex treated coating were investigated by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),micro-hardness,reciprocating wear test machine.The results showed that the duplex treated coating was fully dense,free from cracks and pore defects.The duplex treated coating mainly consisted of Fe and Ni3Si two phases.The micro-hardness of duplex treated coating is 422-436 HV0.3.The duplex tread coating effectively improved wear resistance properties of the cast iron under the dry friction conditions.
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    Drag Reduction and Film-forming Property of Stearic Imidazoline on Natural Gas Pipeline
    XING Wen-guo, FENG Wei-chun, ZHANG Chang-qiao, YU Ping, WEI Yun-he
    2011, 0 (7): 44-48.  
    Abstract ( 306 ( PDF (1065KB)( 144 Citation
    A new natural gas drag reduction agent stearic imidazoline was synthesized according to the drag reduction mechanism and inhibitor mechanism.The mechanism of the film-forming on the iron surface was discussed.The drag reduction efficiency of stearic imidazoline was tested on the drag reduction test loop.The film-forming property of stearic imidazoline was studied by electrochemical characterization and SEM.The results show that stearic imidazoline is adsorbed on the iron surface and smooth membrane is formed.The roughness of the gas pipeline is significantly improved.Under the condition of 8g/L stearic imidazoline and 1h,the maximum drag reduction efficiency is 8.7%.It is a valuable reference to practical industrial development.
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    Influences of Al Content in Packing on Microstructure and Properties of Cr-Al Coating on Cu Substrate Electrodeposited Nickel Layer
    WANG Hong-xing, LI Ying-guang, CHU Cheng-lin
    2011, 0 (7): 49-55.  
    Abstract ( 317 ( PDF (1842KB)( 236 Citation
    The low hardness and poor wear resistance of pure copper result in the less effective use in metallurgical application.In order to increase the microhardness and wear resistance,the pure copper surface with the electro-deposited nickel layer was chromized-aluminized by slurry packing cementation process,and then Cr-Al coating was formed on the surface of Ni plating.The effects of Al powder content on microstructure,microhardness and wear resistance were investigated.The results showed that the phase of coating,which was mainly consists of a solid solution Al and Cr in Nickel,have a preferred orientation in crystal plane(200).As the mass fraction of Al powder increased from 5% to 20%,the microhardness of coating increase gradually from HV 170 to HV 200,and friction coefficient decreases from 0.55 to 0.35.However,when the mass fraction of Al powder was about 25%,the coating with microhardness of 970HV and the friction coefficient of 0.25 was composed of the main phase NiAl and a small amount of Ni2Al3 phase.As a result,the pack process was changed from the chromizing-base to aluminizing-base as the Al powder content increasing.
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    The Application Study of Hybrid Fibers Reinforced Brake Pad for Railroad Coach
    WANG Hai-qing, WANG Cheng-guo, ZHUANG Guang-shan, SUN Yi, YAO Yong-qiang, ZHENG Shu-wei
    2011, 0 (7): 56-60.  
    Abstract ( 340 ( PDF (1174KB)( 216 Citation
    Hybrid fibers were used as reinforced material to product braking pad serviced for railroad coach.The practical application study was conducted according to Railroad Ministry Standard TB/T3118—2005.The thickness of brake pad and disc had been measured on-line,the morphological character of pad and disc was observed.The results showed that hybrid fibers reinforced brake pad had low linear wear rate;and has no cracking,edge-avalanche and scratch.The disc’s exterior view showed the disc’s surface was in proper trim and there was no hot-spot and heat-crack.Tribology analysis indicated that the stable friction film commonly called glace which had been formed as the braking processing with a comparatively steady composition being maintained was beneficial to the surface of pad and disc and to the car’s brakeage.
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    Influence of Surface Roughness and Clean Method on Inspection Value of Oxygen Content for M50NiL Steel
    XIE Xiao-chang, HE Zi-qiang, GENG Xiao-ying, LI Zhi-ming, DONG Cui
    2011, 0 (7): 61-65.  
    Abstract ( 406 ( PDF (926KB)( 152 Citation
    The influence of surface roughness and clean method on the inspection value of oxygen content for M50NiL samples was investigated.The results indicated that the inspection values were step down and tend to steady when surface roughness decreased from Ra3.2 to Ra0.2,and the effective pre-procedure was cleaning by ethanol scrubbing adding acetone ultrasonic washing.The oxygen content inspection values of three kinds of surface roughness(Ra3.2,Ra0.8,Ra0.2) were 6.65×10-6,5.95×10-6,5.55×10-6.The values of different surface roughness samples being very similar were in the range of 5×10-6 and 7×10-6.The samples only disposing by aether obtained much higher oxygen content inspection values,and the acid etching samples showed a little higher oxygen content inspection values undulating with the surface roughness.
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    Experimental Study of the Wear Resistance of TiC/7075 Al Matrix Composite
    LIU Hui-min, SONG Zhen-dong, XU Ping, ZHANG Jing
    2011, 0 (7): 66-69,74.  
    Abstract ( 369 ( PDF (1356KB)( 191 Citation
    The TiC reinforced 7075 Al matrix composites have been fabricated by melt in situ reaction spray deposition.The microstructures of spray-deposited alloys were studied using SEM and TEM.The dry sliding wear behavior of the alloys was investigated using a pin-on-disc machine under four loads,namely 8.9,17.8,26.7 and 35.6N.It has been found that the wear behavior of the alloys was dependent on the TiC content in microstructure and applied load.At lower load(8.9N),with increasing TiC content,the wear rate of the alloy was decreased.At higher loads(26.7,35.6N),spray-deposited 7075 Al alloy exhibited superior wear resistance to the TiC/7075 composites.
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    A Temperature Measuring/Controlling and Experimental Management System for Stress-rupture/Creep Test Machines
    FENG Quan, ZHAO Di, HUANG Xin-yue, ZHANG Zhi-hua, WANG Liang, ZHANG Yan-ming
    2011, 0 (7): 70-74.  
    Abstract ( 346 ( PDF (747KB)( 109 Citation
    This paper describes a temperature measuring and controlling system for hundred old creep testing machines,which have been used around 50 years.The unique design strategy of the developed system is to use independent control and measurement equipments.Under the controlling of the developed system the temperature gradient on specimen is stable even if the specimen length varies,in which case the thermocouple number is different.An effective filtering policy is used so that the temperature measuring and controlling system is not sensitive to the power surges.And the controlling system itself does not make current surges to the power system.The accuracy of the measuring system is less than ±0.1% full scale.The measuring system monitors the temperatures in groups of 30 creep test machines.A computer management software is programmed to scan and record the temperatures of each test machines.The friendly interface of the software allows easy operation and creep testing automation.The temperature measuring and controlling system has been running for about 10 years reliably.A great amount of testing works have been carried out by these testing machines equipped with the developed temperature measuring/controlling system.
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    Magnetic Properties and Mechanical Properties of NBR Composites Filled with Nano-Fe3O4 or Nano-SrO·6Fe2O3
    WANG Qi-lei, YANG Feng-yu, YANG Qian, CHEN Jun-hui, GUAN Hong-yan
    2011, 0 (7): 75-79,84.  
    Abstract ( 408 ( PDF (839KB)( 129 Citation
    The NBR/Fe3O4 composites and NBR/SrO·6Fe2O3 composites were prepared with NBR,nano-Fe3O4 and nano-SrO·6Fe2O3 as raw material.Magnetic properties and mechanical properties of the two composites were studied.The distribution of nano-particles were also analyzed.The results show that when adding different mass fraction of nano-particles,maximum elongation,300% stress at definite elongation and tensile strength of the two composites are decreased.Whereas shore A hardness and mooney viscosity of the two composites are improved.Nano-particles are well distributed in the two composites.Magnetic properties of two composites are closely related with mass fraction of nano-particles.Also,both the two composites have good soft magnetism properties,which lay the foundation for further applications of this kind of composites.
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    Ultrasonic Testing Technique for the Inspection of Defects in the Corner of Composites
    HE Fang-cheng, WANG Zheng, SHI Li-jun
    2011, 0 (7): 80-84.  
    Abstract ( 499 ( PDF (1197KB)( 236 Citation
    Composite material is using in the fields of aviation and aerospace more and more widely.The structure of the composite material is becoming more and more complexly.Corner is one of the complex structures in the composite material parts.Such structure brings new question and challenge for nondestructive testing.Some NDT methods to solve the problem of testing the corner of the composites are introduced in this article,based on the information at home and abroad.The advantage and shortcoming of all kinds of NDT methods for the corner of composites are analyzed.The ultrasonic phased array technology is recommended that can be widely used in the future for testing the corner of composites.
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    A Review on Aging Behaviors of Fiber Reinforced Polymer-matrix Composites
    WANG Yun-ying, LIU Jie, MENG Jiang-yan, ZHANG Jian-ming
    2011, 0 (7): 85-89.  
    Abstract ( 398 ( PDF (862KB)( 406 Citation
    Such environmental factors as hydrothermal and UV have a negative effect on the mechanical properties of fiber reinforced composites,making their strength and stiffness declined.The studies on the artificial climate aging,hydrothermal aging,and thermal oxidation aging of fiber reinforced composites were summarized,and the research results on their artificial accelerated aging and natural aging were introduced.In addition,the studies on the aging property assessment and life prediction of fiber reinforced composites were also summarized.Finally,the disadvantage and trend of the studies on the aging of fiber reinforced composites were pointed out.
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    Cold Crucible Theory and Its Application in Preparing of Multicrystalline Silicon
    HUANG Feng, CHEN Rui-run, GUO Jing-jie, DING Hong-sheng, YANG Jie-ren, SU Yan-qing, FU Heng-zhi
    2011, 0 (7): 90-96.  
    Abstract ( 383 ( PDF (1420KB)( 207 Citation
    The principle,characteristic and technical requirements of cold crucible are reviewed in this paper.The theory,technical parameters and influencing factors of cold crucible are introduced.Effects of technical factors on cold crucible performance are summarized.The advantages and application of purifying and preparing of multicrytalline silicon with cold crucible are overviewed too.Cold crucible technology will be a hopeful and important technique in materials engineering.
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