JIA Panjiang, CHEN Bangfeng. Effect of Microsegregation on Mechanical Properties of ZL205A Casting Aluminum Alloy[J]. Journal of Materials Engineering, 2008, 0(2): 1-4.
The different microsegregation grades of ZL205A casting alloy are gained by the experiment.The effect of microsegregation of ZL205A casting aluminum alloy on the room mechanical properties and fracture surfaces were investigated.The result shows that I grade microsegregation of ZL205A is no obviously effect on the room mechanical properties.The alloy of I grade microsegeration is fit for the design requirement.To compare I grade microsegregation,II grade microgregation has some effect on the normal room mechanical properties of ZL205A alloy,especially more effect on elongation,and that σb,σ0.2 and δ5 decrease 1%,3% and 52% separately.
HU Hongpo, ZHAO Hongsheng, LUO Fa, SHAO Youlin, LIU Bing. Preparation and Characterizations of Fe/Ce Oxidation Nano Glass Coatings[J]. Journal of Materials Engineering, 2008, 0(2): 5-8.
Glass coatings that include iron and cerium oxidations were prepared by citric acid sol-gel and dip-coating method.The UV-VIS-NIR reflection and transmittance,thickness,combination intensity with glass matrix,composition and structure of coating were measured.The results showed that the coating had great combination with the substrate,and it consists of nano holes and nano-crystals.The glass coating could shield most of the ultraviolet and some of the near infrared light,but let more visual light transmitting.When Fe/Ce equal 1:3,heated at 500℃ for 2 hours,the coefficient of UV transmittance is 3.6%,visual light 72.8%,solar energy 60%,and the coefficient of selectivity is up to 1.2 The results indicate that this kind of glass coating has very good UV-sheering and heat-insulating properties,which could be used as an effective solar control glass in automobiles and architectures.
FANG Zhenqian, HU Ming, LIU Bo, SONG Yang. Investigation of the Electrical Properties of Porous Silicon[J]. Journal of Materials Engineering, 2008, 0(2): 9-13,17.
Porous silicon(PS) was prepared in a double-tank cell by using the electrochemical corrosion method and the samples with a Pt/PS/P+-Si/PS/Pt microstructure were obtained.The effects of the etching conditions and post-oxidation process of PS on the transverse I-V characteristics of this kind of microstructure were thoroughly investigated.It was shown that the transverse I-V characteristics of this kind of microstructure were mainly decided by the electrical properties of PS underlayer,which had nonrectifying properties of ohmic contacts.
LI Lingjie, LEI Jinglei, TIAN Yujing, ZHANG Shengtao, PAN Fusheng. Influence of Treating Temperatures on Properties and Performances of Cerium Conversion Coatings on Magnesium Alloys[J]. Journal of Materials Engineering, 2008, 0(2): 14-17.
The influence of four treating temperatures(2,20,50℃ and 70℃) on the growth kinetics,structures,morphologies and anticorrosive properties of cerium conversion coatings on AZ31 magnesium alloy was investigated by gravimetry,X-ray diffraction(XRD),atomic force microscopy(AFM) and electrochemical impedance spectroscopy(EIS).The results show that the treating temperature is crucial to the coating formation,properties and protection performances.As the alloys are treated at higher temperatures,the conversion coatings form more rapidly;the coatings have finer crystal structures and are more intact;the coatings hence provide better corrosion resistance to the substrates.
HUANG Zhirong, SUN Qifeng, LUO Xiaoqiu. Investigation of Alumina Films Deposited on HP40 Alloy by MOCVD and the Property of Coke Formation Inhibition[J]. Journal of Materials Engineering, 2008, 0(2): 18-22.
Thin alumina films were deposited on the heat-resistant steel,type HP40.The deposition process was carried out in nitrogen by atmospheric pressure metal-organic chemical vapor deposition(MOCVD) with aluminum-tri-sec-butoxide(ATSB) as the precursor.The microstructure and coke formation inhibition property of the alumina films were investigated using optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD) and atomic force microscopy(AFM).The results showed that alumina films deposited at 350℃ were nano crystalline,whose surface was smooth,uniform,and dense,and the efficiency of the coke formation inhibition achieved above 52.4%.
DU Nan, ZHOU Haifei, ZHAO Qing, LIAO Qiang. Interfacial Force in Nickel-diamond Composite Electrodeposition and its Effect on Diamond Content in Composite Plating[J]. Journal of Materials Engineering, 2008, 0(2): 23-26,30.
Nickel-diamond composite plating was prepared by composite electrodeposition.Diamond content in composite plating can be controlled to 1.47%-15.6%(mass fraction).It was measured about the attachment ratio of diamond particles on cathode and the interfacial force between diamond particles and nickel coating.The effects of current density,the stirring rate,stirring style,and particle size on diamond content in composite plating were investigated.The results showed that,there must be a little time before particles in cathode surface were rooted in matrix metal.Instead of mechanical occlusive action,it was interfacial force that made particles composite co-electrodeposite with Nickel.The force was close to 3.3 103N/m2.The interim stirring had contributed to improve the content.
FANG Jianjun, QIN Hao, LI Zhuoxin, JIANG Jianmin, SHI Yaowu. Research of High Hardness and Wear Resistance Arc Sprayed Coatings[J]. Journal of Materials Engineering, 2008, 0(2): 27-30.
High hardness and wear resistance coating JCW-B were deposited via arc spraying.The microstructure,porosity,hardness,bond strength and abrasion behavior of JCW-B coating was analyzed,the erosion resistance properties of coating was compared with Arc Spray Welded Ni60 coating.Results showed that JCW-B coating exhibited dense microstructure,low porosity,high hardness,high bond strength and excellent abrasive and erosive wear resistance.XRD spectrum of the coatings indicates that Fe3B was contained as the main hard phase,which dispersedly strengthens the coatings.Moreover,some Fe2O3,FeO were also formed during the spraying process.It was concluded that FeB3 randomly distributed in the microstructure of coating act as hard phase promoting wear properties.
WEN Kai, XU Fumin, TAN Yi. Performance Evaluation of a New Type of Fishplate Material Used for the High-speed Railway[J]. Journal of Materials Engineering, 2008, 0(2): 31-34,39.
This thesis covers the overall evaluation of the tensile and impact properties of a new type of non-quenched-tempered bainite fishplate material at room temperature and low temperature.The research indicates that the microstructure of this type of material is granular bainite of fine crystal,and both of the tensile and impact properties at room temperature and low temperature are superior to that of China B7 steel and the Japanese fishplate materials.In addition,at room temperature and at-55℃ its yield strength is respectively 722MPa and 738MPa,while the elongation is respectively 60.7% and 41.7%.The figures of tensile fractures and impact fractures at varying test temperatures are also observed and shown in the thesis,coupled with the discussion of the crack way of the material.
LI Bin, ZHANG Changrui, CAO Feng, WANG Siqing, CAO Yingbin. Comparison of the Properties of Cf/BN-Si3N4 Composites Reinforced by Two Different Carbon Fibers[J]. Journal of Materials Engineering, 2008, 0(2): 35-39.
The structures,surface compositions and surface morphologies of two different carbon fibers(T300 and T700) were characterized by XRD,XPS and SEM.Two composites with a BN-Si3N4 matrix reinforced by the two carbon fibers were prepared by precursor infiltration and pyrolysis method,and the mechanical properties and microstructures of the composites were investigated through comparison.The results show that the degree of graphitization and surface activity of the two carbon fibers are almost the same;but the surface appearances of them are quite different.The density of the composites reinforced by different carbon fibers is no difference,while the difference of mechanical properties between them is distinct.Compared to T300 carbon fiber,the composite reinforced by T700 carbon fiber exhibits higher flexural strength,slightly lower elastic modulus and much better toughness.The different surface states of different carbon fibers result in different interfacial microstructures and mechanical properties of the composites.
LONG Jianping, WANG Ling, ZHANG Xianghui, SONG Jinliang, CHANG Sihe. Acid Corroding Feature and Etching Depth Quantitative Test for YG series Carbide Cemented Coated Diamond[J]. Journal of Materials Engineering, 2008, 0(2): 40-45,48.
Co concentration in the etching liquor was tested by atomic absorption spectrometry,the etching deepth after different acid corroding time was quantitatively calculated with the AAS test result.Using the methods of multivariate linear regression analysis,the curves of the relation between Co concentration and etching time,and the relation between etching depth and etching time were studied,the regression analysis results were utilize to qualitatively analysis acid corroding feature or quantitatively analysis etching depth.the microstructure of YG series cemented was observed by SEM,Co distribution after definitive etching time in the carbide cemented was analysis by QDP on Glow Discharge optical atomic emission spectrometry.the results show that crystal size and Co concentration of carbide cemented significantly impact on its acid corroding speed,the quantity and geometry shape of grain boundary has the same important effect.Acid corroding speed of YG8 is always faster than that of YG6,but acid corroding speed of YG6X is always slower than that of YG6,furthermore the distinction of acid corroding speed gets greater with etching time going.QDP test results show that the fitting curves of the relation between etching depth and etching time for YG series cemented carbide may be used to celerity analyze etching depth of YG series cemented carbide in aqua fortis liquor before diamond coated.
NI Hongqi, LIU Xianghua, WANG Guodong. Test of Stamping Property for 400MPa Grade Super Steel Sheet[J]. Journal of Materials Engineering, 2008, 0(2): 46-48.
The tensile test,cold bending test and metallographic examination were carried out in 400MPa grade super steel sheet.The hardening exponent,value of plastic strain ratio,yield strength,tensile strength,even percentage elongation and other mechanical performances have been studied.The press forming performance of 400MPa grade super steel has been analyzed.It can be used for guidance of stamping production of super steel in automobile industry.
ZHANG Yani, ZI Jinlei, ZHU Jiewu, ZHENG Maosheng. Influence of Cr Micro-addition on the Corrosion Resistance of Copper Exposed in SO2[J]. Journal of Materials Engineering, 2008, 0(2): 49-53.
The corrosion behavior of cold-rolled copper alloy in humid air containing traces of SO2 was investigated using scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM),so as to understand the influence of microelement Cr on the corrosion resistance of material.The results showed the corrosion resistance of Cu-Cr alloy increases with Cr micro-addition;the increasing of corrosion resistance is strongly related with the compact scales which ensured Cr-contained layers integrated.In contrast,the corrosion resistance of copper alloy is weaken by the local distribution of element Cr.
ZOU Ke, YANG Dongfang, MA Xiangdong. Surface Modification of FeNi Powders and Its Microwave Absorbing Property[J]. Journal of Materials Engineering, 2008, 0(2): 54-57.
Tetraethylorthosilicate(TEOS) was used to modify FeNi powders.The structures of FeNi powders were characterized by means of diffuse reflectance infrared fourier transform(DRIFT),scanning electron microscope(SEM),transmission electron microscope(TEM).The electromagnetic parameters of FeNi powders were tested by network vectorial analysis instrument.The results show that a polymer layer of TEOS was obtained on the FeNi powders surface.Both real part and imaginary part of permittivity of FeNi powders could be lowered by TEOS treatment in the frequency range of(2-18) GHz.As increasing volume content of TEOS,the real part of permeability increased first and then decreased in the frequency range of 3.2-18 GHz.The agglomeration of FeNi powders could be reduced by dispersion and its permittivity decreased greatly.
ZHAO Nairen, WANG Zhihui, LI Jinguo, JIN Tao, SUN Xiaofeng, YANG Hongcai, HU Zhuangqi. Investigation of the Anisotropy for a Nickel Base Single Crystal Superalloy[J]. Journal of Materials Engineering, 2008, 0(2): 58-61.
The microstructure and property of a nickel base single crystal superalloy with various crystallographic orientations of, and has been investigated.The results show that the dendrite morphology and micro-segregation are strongly influenced by crystallographic orientations although the chemical compositions of alloy keep as constant.The Youngs modulus and stress rupture lives of single crystal alloys also exhibit obvious anisotropy.The Young's modulus decreases with the sequence of, and orientation.The longest stress rupture life is obtained in the single crystal with orientation and the alloy with orientation shows the maximum elongation under the testing condition of 871℃/552MPa,while the alloy with orientation appears the longest stress rupture life and the maximum elongation was got in orientation under the testing condition of 1010℃/248MPa.Under the both testing conditions,the alloy with orientation presents the lowest stress rupture life.
ZHANG Wu, KE Liming, XING Li. Investigation of the Cross Section Transfer of Plasticized Materials in Friction Stir Welding for Aluminum Alloy[J]. Journal of Materials Engineering, 2008, 0(2): 62-66.
The transfer of plasticized materials was an important factor for ensure the full metallurgy of weld in friction stir welding.The material transfer in the cross section was visualized by lamella structure plates made up with thin copper foils and aluminum plates.It is shown that,In the cross section of the weld,the materials adjacent the pin will move downwards along the surface of the pin and the materials a little far from the pin which have counter-clockwise screw thread features will move adversely.Which make materials do circulate movement in the thickness of the weld.It was not symmetry about weld centerline the area which the material had deformed.The plasticized materials looked like a slantwise vase in the center of the weld.The width of the plasticized region became narrow form the top of the weld to the bottom of the weld,the plasticized materials where at the advancing side upwards to the top of the weld was smaller than the retreating side,The width of the plasticized region where at the advancing side was smaller than retreating side.
LI Ping, GUO Feng, WANG Hangong. Study on Microhardness Characteristic of Coatings Ti-Al Twin Wires Ultrasonic Arc Sprayed[J]. Journal of Materials Engineering, 2008, 0(2): 67-70,75.
Using commercial titanium and aluminum wires,Ti-Al composite coatings were prepared on the substrate of LY12 aluminum alloy by ultrasonic arc spray equipments of SAS-II,and microhardness of coatings were determined.The results of experiments were analyzed by experiments project based on uniform design theory and the quadratic polynomial stepwise regression analysis method and a regression model between microhardness of coatings and technology parameters was obtained with significance level of 0.002 and correlation coefficient of 0.98.The further analysis results showed that microhardness of coatings decreased with increased spraying voltage at lower current;microhardness of coatings increased with increased spraying voltage at higher current,moreover,the increasing rate increased with increased current;microhardness of coatings increased with increased spraying distance linearly.
WANG Hong, ZHANG Jun, CUI Chunjuan, LIU Lin, FU Hengzhi. Directional Solidification of Monocrystal Refractory Metal with Electron Beam Floating Zone Melting[J]. Journal of Materials Engineering, 2008, 0(2): 71-75.
Refractory metals and alloys with outstanding properties play an unsubstituted role in the fields of national defence,aerospace,electronics,energy sources,chemical engineering,metallurgy and nuclear industry,and attract much more attention recently.The application and development of the refractory metals and alloys are reviewed.As an example of monocrystal W,Mo and alloys,the development of the directional solidification technology with electron beam floating zone melting for the preparation of refractory metal monocrystal is summarized.The processing and microstructure of molybdenum produced by electron beam zone melting is also preliminarily investigated.
LIU Yuyan, MENG Qiuying, TAN Huifeng, DU Xingwen. The Situation of the Rigidizable Materials and Rigidization Technology Used in Space Inflatable Structures[J]. Journal of Materials Engineering, 2008, 0(2): 76-80.
The rigidizable materials and rigidization technology are the key technologies of space inflatable structures.Rigidizable materials can be classified into several categories base on their base materials properties.There are thermosetting composites,thermoplastic(and lightly cross-linked thermosetting) composite materials,and aluminum/polymer laminates.This paper reported the typical rigidization technology of these rigidizable materials.The characteristics and current situation of each rigidization system were introduced respectively.And the major benefits and limitations of these rigidization technologies were also discussed.
