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  • 2008 Volume 0 Issue 3
    Published: 20 March 2008
      

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  • ZHAO Cheng-zhi, WEI Shuang-sheng, WU Gui-xiang, WANG Yan-hua
    2008, 0(3): 1-4,76.
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    ZHAO Cheng-zhi, WEI Shuang-sheng, WU Gui-xiang, WANG Yan-hua. Fracture Characteristic and Strengthening Mechanism of Heat Resistant Steel ZG1Cr10MoWVNbN[J]. Journal of Materials Engineering, 2008, 0(3): 1-4,76.

    The microstructures of the heat resistant steel ZG1Cr10MoWVNbN were analyzed by means of metallography,SEM and TEM.The fracture characteristics were studied using the method of fracture analysis.The strengthening mechanisms were also studied.The results show that the microstructure of the steel consists of lath shape martensite,which contains a great number of high density dislocations and substructures,that in the microstructure,the carbides,nitrides and carbonitrides distributes dispersively.They also show that the fractures of the specimen are quasi-cleavage ones,and the materials posses not only higher strength,but also higher toughness;that the strengthening mechanism includes martensite strengthening,solution strengthening,carbide strengthening,nitride strengthening and carbonitride strengthening.
  • ZHANG Yong, ZHANG Guo-qing, HE Zhi-yong, FENG Di, LI Zhou
    2008, 0(3): 5-8.
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    ZHANG Yong, ZHANG Guo-qing, HE Zhi-yong, FENG Di, LI Zhou. Wettability Research of Nickel-based High Temperature Filler Metal on Cf/SiC Ceramic Matrix Composite[J]. Journal of Materials Engineering, 2008, 0(3): 5-8.

    The influence of temperature and active element chromium to wettability of several nickel-based high temperature filler metals on three-dimension carbon fiber reinforced silicon carbide composite(3D-Cf/SiC) was studied in this paper.Additionally,the interfaces between filler metals and Cf/SiC were inspected using scanning electron microscopy(SEM),energy dispersive spectroscopic(EDS) analyses and X-ray diffractometry(XRD).It was found that the contact angle decreased with the temperature rising,also the mass fraction of element chromium has much influence on the wettability,the content of chromium increases,so the contact angle decreases.The wetting procedure is reactive wetting,and several carbides and silicides were made at interface.
  • WANG Can-yao, ZHENG Yu-ying
    2008, 0(3): 9-12.
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    WANG Can-yao, ZHENG Yu-ying. The Isothermal Crystalline Kinetics and Melting Behavior of Nylon 6 Composites Treated by Kevlar Fiber[J]. Journal of Materials Engineering, 2008, 0(3): 9-12.

    Kevlar fiber was modified by anionic graft of nylon 6 oligomer.Nylon 6/modified Kevlar fiber(PA6/KF1) composites were prepared by extrusion and injection process.XPS,ESEM and FTIR proved the nylon 6 oligomer was grafted onto the surface of Kevlar fiber.DSC was used to study the effect of KF0 and KF1 on the isothermal crystalline kinetics and melting behavior of PA6/KF composites.The results have shown that the KF played an role of heteregeneous nucleation agent in the process of crystallization of PA6 and increased its crystallization rate.The improved interfacial adhesion between PA6 and KF1 in the composites restricted the motion of PA6 segments,which thus leading to the demotion of heteregeneous nucleation of PA6/KF1.At low temperature(188-192℃),the melting behavior of PA6 presented triplet peaks after isothermal crystalline,while the melting behavior turned up double peaks at relatively high temperature(194℃).The induction of KF has influenced the melting behavior of PA6 dramatically.
  • LI Xiao-fei, LI Xiao-hong, XIONG Hua-ping, LI Yan
    2008, 0(3): 13-17.
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    LI Xiao-fei, LI Xiao-hong, XIONG Hua-ping, LI Yan. Process Investigation on Automatic Tungsten Inert Gas Welding of Aluminium-lithium Alloy[J]. Journal of Materials Engineering, 2008, 0(3): 13-17.

    With two developed wires,aluminium-lithium(Al-Li) alloy was welded by Automatic Tungsten Inert Gas Welding.The mechanical properties,microstructure of the joint and fracture morphology of tensile samples were investigated.The susceptibility to hot crack of the test alloy was also assessed through houldcroft cracking test.The experimental results show that the process specifications greatly affect the formation of weldment.Using alternating current(AC) impulse welding and with the developed wires as filler metal,the resistance to hot crack of the experimental alloy was improved significantly.The as-welded joint strength reach 60% of that of the base metal.
  • WANG Jin-feng, GAO Ya-chun, XIE Zhi-peng, SUN Jia-lin
    2008, 0(3): 18-21,27.
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    WANG Jin-feng, GAO Ya-chun, XIE Zhi-peng, SUN Jia-lin. Preparation of Ultrafine Zirconia Suspension for Gelcasting[J]. Journal of Materials Engineering, 2008, 0(3): 18-21,27.

    Properties and preparation of ultrafine ZrO2(d0.5=0.199μm)suspension in gelcasting were investigated.It is proved that A-type dispersant is suitable for the suspension and the amount of it is 2%-2.5% of ZrO2.pH value of suspension should range from 10 to 11.Milling time of slurry is about 12h.ZrO2 suspension was prepared with 54% solid loading,viscosity of which was 0.952 Pa.s and it could be used in gelcasting process.The bending strength of green body was 50.09 MPa and the sintered ZrO2 ceramics with fine crystal compact structure was produced at 1550℃ holding 2h.
  • ZHAN Mei-yan, LI Yuan-yuan, CHEN Wei-ping, CHEN Wan-de
    2008, 0(3): 22-27.
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    ZHAN Mei-yan, LI Yuan-yuan, CHEN Wei-ping, CHEN Wan-de. Microstructure and Mechanical Properties Evolution of AZ31 Sheets During Accumulative Roll-bonding[J]. Journal of Materials Engineering, 2008, 0(3): 22-27.

    Accumulative roll-bonding was performed on AZ31 magnesium alloys.The evolution of microstructure and mechanical properties of AZ31 sheets during accumulative roll-bonding was researched.The results show that accumulative roll-bonding provides a simple,effective and inexpensive technology to prepare large-sized AZ31 Mg alloy sheets with fine grains and improved ductility at ambient temperature.AZ31 sheets with fine grains about 1-2μm was successfully achieved by accumulative roll-bonding after 5 cycles.The grain refinement during ARB can be owing to the severe accumulated strain and shear strain in the surface of the sheets.The best compromise between strength and ductility of ARBed AZ31 sheets is obtained after 5 cycles.In this case,the average ultimate tensile stress is 349MPa and average tensile elongation is 22.46%.The strengthening and ductility increasing can be attributed to the occurrence of significant grain refinement.However,grain growth occurs easily by reheating between ARB cycles,which will partly cancel out the grain refinement causing by accumulated strain.
  • DAI Ya-chun, WANG Yun, ZHOU Jian-zhong
    2008, 0(3): 28-31,53.
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    DAI Ya-chun, WANG Yun, ZHOU Jian-zhong. Simulation of Micropart’s Weld Lines by Injection Molding[J]. Journal of Materials Engineering, 2008, 0(3): 28-31,53.

    With the increasing demands of plastic microparts,microinjection process is becoming the focus as it is the main method for producing the microparts with high precision in batch.However,compared with the conventional injection process,the minimization of parts’ dimensions has brought the problems such as the theory,process,equipment and measurement.As the gating system,the positions and numbers of melding lines are the main concerns influencing the microparts quality.In this paper,the numerical simulation has been carried on to obtain the process parameters difference between the microinjection and conventional injection.The results show that the temperature,pressure and velocity of microinjection are higher than conventional process,and the temperature is the key factor to ensure the success of microinjection.Furthermore,the mould temperature should be high than the vitrification point of polymeric material,and the temperature of microparts needs to be control efficiently.
  • YU Xiao-zheng, SHEN Zhi-gang, XU Zheng
    2008, 0(3): 32-35.
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    YU Xiao-zheng, SHEN Zhi-gang, XU Zheng. Plating Metal Film on the Surface of Carborundum Particles by Magnetron Sputtering Method[J]. Journal of Materials Engineering, 2008, 0(3): 32-35.

    The metal copper films were deposited on carborundum particles by direct current magnetron sputtering method under different working conditions.The surface morphology,chemical composition,film grain size as well as the film crystallization of particles were analyzed by field emission scanning electron microscopy(FESEM),energy dispersive spectroscopy(EDS),inductively coupled plasma-atom emission spectrometer(ICP-AES) and X-ray diffraction(XRD) respectively before and after the plating process.The effects of different sputtering conditions on crystallization of copper films deposited on particles were discussed.The results indicate that the relatively uniform,continuous and adhesive metal films were successfully deposited on particles through controlling the motion mode of particles during film growth.With the increasing of sputtering time or the sputtering power or the substrate temperature,both crystallization and grain size of metal film were improved.
  • HOU Nai-xian, YUE Zhu-feng, YU Qing-min, YU Kua-hai, ZHU Zhen-tao
    2008, 0(3): 36-39.
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    HOU Nai-xian, YUE Zhu-feng, YU Qing-min, YU Kua-hai, ZHU Zhen-tao. Experiment and Theory Investigation on Tension Behavior of Thin-walled Cylindrical Specimen at Temperature Gradient[J]. Journal of Materials Engineering, 2008, 0(3): 36-39.

    The test system at high temperature gradient was developed,and thin-walled cylindrical specimen was designed to carry out tension test at different temperatures and different temperature gradient.Practical method combined with finite element analysis to determinate the relation between stress and strain was developed.Distributions of temperature in specimen were obtained from coupled analysis of flow field and solid,and the temperature was transferred to FEM model by interpolation code.Based on the relation between true stress and true strain at different temperatures,the FEM simulation was carried out at temperature gradient.The result shows that the present temperature gradient has little influence on the tension behavior of specimen.And in this cose it is suitable to investigate the tension behavior of specimen with the usual numerical method.
  • DU Hong-kui, KONG Fan-yu
    2008, 0(3): 40-43.
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    DU Hong-kui, KONG Fan-yu. Crack Initiation and Propagation of Small Defect in Low Alloy Steel[J]. Journal of Materials Engineering, 2008, 0(3): 40-43.

    Crack initiation and growth from small hole and the determining of the size effects of small defects in low cyclic fatigue lives of steel bar were investigated.The specimens chosen was 16MnR steel,normally for fabricating pressure vessels in china,with drilled hole of different sizes on surface,say from 40,80,100,200μm in diameter.It has been observed that one types of crack initiation mechanism at the edge of surface small hole are possible.One is caused by slip bands in which the shear stress dominates,while the other is caused by so-called dispersing initiation in which the normal stress dominates.The size of small defect affects the fatigue life apparently,but the effect weakens with increasing stress level.In certain stress level,there is a critical value of the size of small defect,and beyond which,the fatigue life will drop greatly.
  • LI Yan, LIU Ning
    2008, 0(3): 44-48.
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    LI Yan, LIU Ning. Effect of Carbon Content on the Microstructure and Mechanical Properties of(Ti,W)(C,N)-Co Cermets[J]. Journal of Materials Engineering, 2008, 0(3): 44-48.

    Ti(C,N)-Co cermets were prepared by vacuum sintering with sub TiC,nano TiN,Co as a binder,and the microstructure and mechanical properties of Ti(C,N)-based cermets were also studied.Results show that the microstructures of cermets exist black core-grey rim structure and white core-grey rim structure.The amount of white core-grey rim structure increases,the carbonitride grain size increases with increasing carbon content.Results also show that the transverse rupture strength and the hardness have the similar trend,the good fracture toughness can be obtained when the addition of C is high.
  • FANG Jian-feng, TIAN Zhi-ling, YAN Ping, ZHANG Jin-yuan, ZHENG Yi
    2008, 0(3): 49-53.
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    FANG Jian-feng, TIAN Zhi-ling, YAN Ping, ZHANG Jin-yuan, ZHENG Yi. A Study of Determination of Orientation of Ni-based Single Crystal Superalloy[J]. Journal of Materials Engineering, 2008, 0(3): 49-53.

    A principle for determining the orientation of [001] crystal direction of Ni-based single crystal superalloy has been explained by asymmetrical X-ray diffraction technique in common diffractometers.It is based on Omega(which is the angle between the incidence X-ray beam and the surface of the sample tested) scanning while the 2θ angle keeps constant.Three[001]-oriented Ni-base superalloys which have different orientation angles have been tested by the method developed in this work.The range of orientation angle in Ni-based single crystal which can be tested by this method and the possible way to extend the range are discussed.The diffraction line of(002) crystal plane of Ni-based single crystal has been attained by asymmetrical diffraction technique with certain offset angle.The significance to attain the diffraction line is evaluated.
  • GAO Shuang-sheng, GANG Tie, HUANG Zong-ren
    2008, 0(3): 54-57.
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    GAO Shuang-sheng, GANG Tie, HUANG Zong-ren. Extracting and Sizing of Weak Defect Region in an Ultrasonic Image of Cu-steel Surfacing[J]. Journal of Materials Engineering, 2008, 0(3): 54-57.

    A method combined with global and dynamic threshold image segmentation is proposed,and by which weak defect regions in the ultrasonic C-scan image of Cu-steel surfacing are segmented effectively.The principles of global threshold and dynamic threshold and the proposed image segmentation method are presented and the image processing results are compared.In order to verify the reliability of proposed method,destructive experiments are carried out and the defects are measured in length along the interface.It shows that the destructive results are consistent with the measure result in processed image.The proposed method can distinguish weak defect region from background image with small errors.
  • YUN Yue-hou, LIU Yong-lin, ZHANG Wei
    2008, 0(3): 58-62.
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    YUN Yue-hou, LIU Yong-lin, ZHANG Wei. Study on Microwave Absorption Properties of NanometerNi0.5Zn0.5CexFe2-xO4 Ferrite by Chemistry Co-precipitation Method[J]. Journal of Materials Engineering, 2008, 0(3): 58-62.

    Nanometer Ni0.5Zn0.5CexFe2-xO4(x=0,0.005,0.01,0.015) were prepared by the chemistry co-precipitation method,and microwave absorption coefficient in the rage of 8.2-12.5GHz were measured by AV3618 net analyzing apparatus.It shows that the content changing of Ce would affect the microwave absorbing properties.When the thickness of Ni0.5Zn0.5CexFe2-xO4 is 1.0mm and x=0.01,the capability of microwave absorbing is the best one.There are three absorption peaks;The maximum absorption quantity is 15.4dB when the frequency is 8.8GHz,and effective band width reaches 3.8GHz above 10dB.So adulteration of appropriate amount of rear earth Ce is an effective way to improve the microwave absorbing properties of the Ni-Zn ferrite.
  • YU Ping, WANG Lei-lei, XING Wen-guo, ZHANG Chang-qiao, WEI Yun-he
    2008, 0(3): 63-66.
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    YU Ping, WANG Lei-lei, XING Wen-guo, ZHANG Chang-qiao, WEI Yun-he. The Composition and the Electrochemistry Corrosion Behavior of Hot-dip Zn-Mg Alloy Coated Steel Sheet[J]. Journal of Materials Engineering, 2008, 0(3): 63-66.

    Using electrochemistry experiment,salt spray tests and accelerated corrosion experiment,under the ocean atmospheric corrosion and the polluted air corrosion environment,the corrosion behavior of different composition of hot-dip Zn-Mg alloy coated steel sheet was studied.It was found that the Zn-Mg alloy coated steel sheet has excellent corrosion resistance both under the ocean atmospheric corrosion and the polluted air corrosion environment.But in the production,the preferable Mg content is 1%-2%.
  • CHEN Chang-zi, LENG Yong-xiang, SUN Hong, ZHU Sheng-fa, BAI Bin, ZHANG Peng-cheng, HUANG Nan
    2008, 0(3): 67-71.
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    CHEN Chang-zi, LENG Yong-xiang, SUN Hong, ZHU Sheng-fa, BAI Bin, ZHANG Peng-cheng, HUANG Nan. Microstructure and Properties of Commercial Pure Iron Modified by High Frequency and Low Voltage Plasma Immersion and Ion Implantation(HLPIII)[J]. Journal of Materials Engineering, 2008, 0(3): 67-71.

    Commercial pure iron was modified by high frequency and low voltage plasma immersion and ion implantation(HLPIII) at different pulse duration.The microstructure,the surface elemental contents,microhardness and wear resistance were characterized with X-ray diffraction(XRD),XPS,scanning electron microscope(SEM),HXD1000 microhardness meter,CSEM pin-on-disk wear test apparatus.The corrosion resistance was evaluated using anodic polarization tests in 0.9% NaCl solution.The results showed that plasma nitriding on commercial pure iron at different pulse duration can obviously enhance microhardness,wear resistance and corrosion resistance.The microstructure of the nitrided layers was Fe3N and Fe4N,and there was some needle-like structure in the layer.The high pulse duration was helpful for improving mechanical property and corrosion resistance of the commercial pure iron nitrided layers.
  • XIE Wei, CHENG Hai-feng, CHU Zeng-yong, CHEN Zhao-hui
    2008, 0(3): 72-76.
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    XIE Wei, CHENG Hai-feng, CHU Zeng-yong, CHEN Zhao-hui. Development on Preparation of Magnetic Metallic Fiber Absorbers[J]. Journal of Materials Engineering, 2008, 0(3): 72-76.

    Magnetic metallic fibers are some novel absorbers for radar absorbing materials.Its magnetic anisotropy and absorbing mechanism are reviewed in detail.The preparation processes and devices are introduced here.The advantages and disadvantages of their preparation are also compared.The development of the magnetic metallic fiber absorbents and the prospect of this field are put forward.
  • ZHAO Ya-qi, WANG Cheng-guo, ZHU Bo, WANG Yan-xiang, WANG Qi-fen
    2008, 0(3): 77-80.
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    ZHAO Ya-qi, WANG Cheng-guo, ZHU Bo, WANG Yan-xiang, WANG Qi-fen. Research on the Initiation Mechanism of Aqueous Deposited Polymerization of Acrylonitrile[J]. Journal of Materials Engineering, 2008, 0(3): 77-80.

    The initiation mechanism of aqueous deposited polymerization of acrylonitrile initiated by inorganic initiators was reviewed.Ionic radicals were easily produced to initiate the aqueous deposited polymerization of acrylonitrile in the presence of main oxidants,such as persulfate and chlorate in the inorganic initiation systems.
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