DU Zhi-ming, CONG Sen, LIU Jun, QIN Jin, XIE Shui-sheng. Theory Analysis of Forming Limit for Hot Extrusion Process of Aluminum Alloy Axisymmetric Flange Parts[J]. Journal of Materials Engineering, 2011, 0(8): 1-4.
The influence factors and rules of the forming limit of aluminum alloy axisymmetric part in the hot extrusion process were theoretically analyzed.Through setting up the mechanical model of the stress state in the hot extrusion process of aluminum alloy axisymmetric flange parts,obtain the expression of the stress state and the maximum diameter in flange region.At the same time,through the comparison of different stress conditions.The regulation of the pressure P in the outer of flange,the friction τ between the material and tool and the thickness t of flange region for the maximum diameter in flange region was analyzed,in order to offer theoretical basis for predicting the forming limit.
LIU Shi-yong, ZENG Xiang-bo, PENG Wen-bo, YAO Wen-jie, XIE Xiao-bing, YANG Ping, WANG Chao, WANG Zhan-guo. Optimization of Double Nanocrystalline Silicon p-layers for Amorphous Silicon Solar Cells[J]. Journal of Materials Engineering, 2011, 0(8): 5-7,13.
The plasma enhanced chemical vapor deposition(PECVD) system was used for fabricating the silicon films with different hydrogen dilution ratio(RH) under the high power density,high pressure and low substrate temperature.High-resolution transmission electron microscopy(HRTEM) and Raman spectroscopy indicated that the thin films were nanocrystalline silicon(nc-Si) films which contained nanocrystallites with grain size around 3-5nm.The effects of the RH on the optical band gaps of the nc-Si thin films were studied.The results showed that the optical band gaps of the nc-Si thin films increased with the increased in the RH.An double nc-Si p-layers structure was developed to improve the i/p interface in hydrogenated amorphous silicon(a-Si:H) solar cells.The efficiency of the double nc-Si p-layers cell was improved by 17% compared its counterpart of the single nc-Si p-layer cell.
TIAN Zhi-qiang, KONG Xiao-dong, WU Gang, WANG Yuan-sheng. Study of Early Corrosion Behavior for 12Cr1MoV Heat-resistant Steel in Solution with NaHCO3 by Electrochemical Noise[J]. Journal of Materials Engineering, 2011, 0(8): 8-13.
The early corrosion behavior for 12Cr1MoV heat-resistant steel in distilled water contained 0.5mol/L NaHCO3 and Cl-of different concentration was investigated by electrochemical methods.The noise spectra of 12Cr1MoV in different corrosion condition were recorded by electrochemical noise(EN) technique,and the conclusions were proved by appearance of corrosion observation,polarization tests and microcosm analysis.The results showed that the corrosion products film formed by the action between substrate surface and HCO3,the passive film was destroyed with the addition of Cl-,typical potential spectra of pitting occurred,and then the metastable pitting was fixed by HCO-3.The initiation rate(λ) of metastable pits increased,the period of pits initiation condensed with Cl-concentration increasing.The conclusions of polarization tests,appearance of corrosion observation and microcosm analysis agreed well with the conclusions of EN analysis.
QU Yan-ping, LIU Li-rong, ZU Guo-qing, JIN Tao, HU Zhuang-qi. Microstructural Evolution of Recrystallization During Heat Treatment in DD6 Single Crystal Superalloy[J]. Journal of Materials Engineering, 2011, 0(8): 14-18.
Microstructural evolution of recrystallization during heat treatment in DD6 single crystal superalloy were investigated.The results showed that during pre-treatment at the temperature up to as-cast γ′ phase solvus,no recrystallization occurred,while after solution treatment,rapid recrystallization occurred.During preheat treatment above the temperature,recrystallization occurred.The recrystallization grain boundary was thin and composed of bigger γ′phase.Compared with the microstructure after solution treatment,the recrystallization depth after aging treatment had no obvious change.During aging treatment,grain boundary turned into wider cellular structure and some granular M6C carbide precipitated from grain boundary.
LIU Wan-ying, SHI Tai-he, ZENG De-zhi, ZHU Ze-hua, JIA Hua-ming, LU Qiang, LIU Peng. Study on Drill Pipe with Mud Membrane Corrosion Mechanics Under Atmospheric Environment[J]. Journal of Materials Engineering, 2011, 0(8): 19-23.
High temperatures and pressures autoclave were used to simulate the field environment of Tarim oil deposit.And corrosion behavior and mechanism of S135 drill pipe in lignosulfonate mud were studied.Topographic features of mud cake adhereing to the drill pipe and the corrosion product of drill pipe were analyzed by XRD and SEM.The results showed that S135 drill pipe emerged local oxidation corrosion.Features were ulcer-like corrosion and local contiguous corrosion and pit corrosion.Main corrosion products were orthorhombic crystal system's allcharite.The main reason of drill pipe corrosion was unscraped mud while hoisting.Moisture from mud membrane volatilized on the air and formed mud cake shell.Then iron hematite,barite,bentonite powder,and calcium powder were left as the framework for solid phase substrates.That was called scale buildup.It contacted drill pipe's surface and three interrelated local corrosions,which were differential oxygen concentration,bimetallic corrosion and crevice corrosion,were produced.
LIU Wei-wei, LI Ying, LIU Shi-zhong, LI Jia-rong. Thin-wall Stress Rupture Properties of Single Crystal Superalloy DD6 with [011] Orientation[J]. Journal of Materials Engineering, 2011, 0(8): 24-27.
Thin-wall stress rupture properties of the second generation single crystal superalloy DD6 with orientation were investigated at 760,980℃ and 1070℃.The results show that the stress-rupture lives of thin-wall specimens are equivalent to those of standard specimens.The microstructures of the alloy were studied at 760℃/590MPa,980℃/270MPa and 1070℃/270MPa,the γ′phase occurs local deformation at 760℃,and the directional coarsening γ′phase occurs and the rafting is formed at 980℃ and 1070℃.
XU Bo, WANG Shu-lin, LI Sheng-juan, LI Lai-qiang. ZnFe2O4 Nano-structure Preparation via Water Splitting Reaction and Mössbauer Spectrum Analysis[J]. Journal of Materials Engineering, 2011, 0(8): 28-31.
ZnFe2O4 nano-particles were manufactured by hydrolyzing Zn/Fe3O4 nano-particles,and the ingredient and morphology of the product were tested by XRD and TEM in order to examine and verify the water splitting process equations to be true.The results indicated that the product included ZnO nano-rods at 260℃.The ZnO nano-rods disappeared gradually when the reaction temperature rose to 300℃,and then relatively pure ZnFe2O4 nano-particles were gained.Mössbauer spectrum of the product presented a well defined sextet spectrum,and its crystal structure was a mixed spinel structure.The product took on antiferromagnetism with a magnetic nonrandom structure.
WANG Jing-feng, WEI Yi-yun, WU Xia, PAN Fu-sheng, TANG Ai-tao, DING Pei-dao. Microstructure and Compression Properties of As-cast,As-extruded and Rapid Solidified ZK60 Magnesium Alloy[J]. Journal of Materials Engineering, 2011, 0(8): 32-35,41.
Rapid solidified ZK60 magnesium alloy was prepared by copper mold casting.The microstructure of the as-cast,as-extruded and rapid solidified ZK60 magnesium alloys were analyzed by X-ray diffractometer(XRD) and scanning electron microscope(SEM).The results show that the microstructure of rapid solidified ZK60 magnesium alloys are refined and MgZn phases in dispersed particles are uniformly distributed in the matrix.In addition,the eutectic microstructure with high Zr content can be found in the matrix.The compression strength of rapid solidified ZK60 magnesium alloys were higher than those of as-cast and as-extruded conditions,e.g.an ultimate strength of 444MPa in rapid solidified ZK60 magnesium alloys.
FEI Jun, HU Yan-hong, HUANG Fa-rong, DU Lei. Investigation on Interface of AZ-1 Modified Carbon Fiber Reinforced Polytriazole Composites[J]. Journal of Materials Engineering, 2011, 0(8): 36-41.
Interface modification effect and mechanism of novel polytriazole-matrix composites with the treatment of carbon fiber by aziridine were studied.The carbon fibers were modified by nitric acid oxidation followed with introduction of the coupling agent AZ-1 containing aziridine ring.The results showed that the interlaminar shear strength(ILSS) of treated carbon fiber/polytriazole composites was improved almost by 86% compared with untreated composites.AFM,SEM and contact angles characterizations suggested chemical modification could enhance surface roughness and polarity,and improve ILSS of carbon fiber/polytriazole composites.XPS results further indicated that acidic groups were introduced onto surface after nitric acid oxidation,then the aziridine ring of AZ-1 would be opened to create amine compounds onto the surface of oxidized carbon fiber at room temperature,which improved effects of the interface between polytriazole and carbon fiber.
WEI Wen-juan, TANG Hai-jun, FENG Qiang. Effects of Surface Treatment on Cellular Recrystallization of a Second-generation Single Crystal Superalloy[J]. Journal of Materials Engineering, 2011, 0(8): 42-47.
The effects of surface processing and heat treatment conditions on cellular recrystallization behaviors were investigated in a 2nd generation Ni-base single crystal superalloy after different surface treatment and then heat treating at 1000-1200℃ under vacuum condition.The results indicated that the cellular microstructure after heat treatment was observed in all specimens and the thickness of cellular recrystallization zone increased with the surface processing of grinding,grit blasting and shot penning,respectively.The thickness of the cellular layer was up to 0.1mm in shot penning samples after heat treating at 1200℃ for 50h.And low-angle boundaries lower than 5° and high-angle boundaries within the range of 35-45° for misoriented angles existed not only between different cellular colonies,but also between the cellular recrystallization zone and the substrate.In addition,the heat treatment temperature played a more significant role than the holding time in the change of growth rate and layer thickness for the cellular recrystallization.
ZHANG Guan-li, WU Jian-hua, HUO Zhong-qi, ZHANG Xiao-feng. Properties of Transparent Conductive Film with Acrylic Resin Coating[J]. Journal of Materials Engineering, 2011, 0(8): 48-51.
The acrylic resin coating was used before and after magnetic sputtering of transparent conductive film on the PMMA to improving environmental resistance.The properties of transparent conductive film with acrylic resin coating were inquired.The results showed that the environmental resistance of transparent conductive film was significantly improved after using the acrylic resin coating.The acrylic resin coating could be used as a antireflection layer because of its low refractive index.The quality of film sputtering on the acrylic resin coating was improved as the using of acrylic resin coating.
QIAN Qing-sheng, LI Hai, WANG Zhi-xiu , WANG Xiu-li, SHI Zhi-xin. Microstructure and Oxidation Resistance Behavior of Hot Dip Aluminized Coating on HP40Nb Steel[J]. Journal of Materials Engineering, 2011, 0(8): 52-57.
In order to improve the high temperature oxidation resistance of HP40Nb steel,experiments of hot-dipped and different diffusion treatments were carried out.The oxidation resistance behavior of the diffusion treatments specimens were studied at 1000℃.The effect of diffusion treatment on hot dip aluminizing steel microstructure and oxidation resistance behavior at high temperature was studied by means of SEM,EDS and XRD.The results showed that the specimens after diffusion at 800℃ for 4h,the coating consisted of inner layer(NiAl+Cr3Si),intermediate layer(Fe2Al5+small amount Ni2Al3) and outer layer(FeAl3).After diffusion at 900℃ for 4h,the coating consisted of inner layer(NiAl+Cr3Si) and outer layer(Fe2Al5+small amount Ni2Al3).After diffusion at 1000℃ for 4h,the coating consisted of inner layer(α+Ni3Al,NiAl+Cr3Si) and outer layer(Fe2Al5+Ni2Al3).After the cyclic oxidation test at 1000℃ for 360h,the coating consisted of outer layer(NiAl+Cr3Si) and inner layer(σ,α+Ni3Al).The oxidation resistance of the specimen which was diffused at 1000℃ for 4h was best,and the rate of mass gain is 13% of the uncoated aluminum layer specimen.It obviously increased the high temperature oxidation resistance behavior owe much to α-Al2O3 scales on the surface of HP40Nb steel during high temperature oxidation process.Moreover,the oxidation resistance of the aluminized coating increased with increasing the diffusion temperature.The presence of σ phase in the coating retarded the inward diffusion of Al in the coating,therefore the coating layer which was gradually consumed due to acting as an aluminum source formed a protective α-Al2O3 at the coating surface after oxidation.The intermetallic compound NiAl and Cr3Si really played an important role of high temperature oxidation resistance except α-Al2O3 scale.
WANG Dong-mei, ZHANG Xue-bin, LIU Li-hua, WANG Feng, XU Kang. Electroless Nickel Plating of Nano-attapulgite[J]. Journal of Materials Engineering, 2011, 0(8): 58-61,67.
The raw attapulgite mineral was purified into nano-fibers and the nano-purification of attapulgite was modified by electroless plating a continuous layer of nickel on it.The effects of pre-treatment on the electroless nickel plating of attapulgite were analyzed by transmission electron microscopy(TEM) and X-ray diffraction(XRD).The results showed that by adding activated sites before electroless plating,the surface of attapulgites can be coated with layer of nickel.And it is difficult to gain continuous uniform distribution elcetroless plating layer for attapulgites because of its large proportion of longitudinal axis length and diameter,and its weak reaction capacity.Therefore,further optimization way of pre-treatment(especially coarsening and activation) and process parameters were needed to be successful coated with complete layers of nickel on attapulgites.
FENG Pei-jie, SONG Li-xian, LU Zhong-yuan, LU Ai. Study on High Temperature Vulcanising Silicone Rubber Foamed by Supercritical Carbon Dioxide[J]. Journal of Materials Engineering, 2011, 0(8): 62-67.
The feasibility of silicone rubber foam prepared by supercritical carbon dioxide was investigated.Adopting the "precured-foamed-fully cured" process,the effect of the foaming temperature,pressure,swelling time and depressurization time on the density and foam structure of silicone rubber foam was studied.The foam structure was analyzed by scanning electron microscopy(SEM).The results showed that the silicone rubber foam with small pore size(<100μm),uniform and controllable foam structure was formed by use of supercritical carbon dioxide.
ZHENG Yu-ying, LIAO Shi-jun, HUANG Hui-min, WANG Qiao-yun. Preparation and Characteristic of NiO-YSZ Nanocomposite Powders[J]. Journal of Materials Engineering, 2011, 0(8): 68-71.
NiO-YSZ nanocomposite powders were successfully prepared by ultrasonic co-precipitation method,with ZrOCl2·8H2O,Y(NO3)3·6H2O,NiSO4·7H2O as raw materials.The morphology,crystal structure and reducing process of the products were studied by TPR,XRD and TEM etc.The conductivity of Ni-YSZ with different Ni content was determined through the Four-terminal electrode method.The results showed that the products were small diameter,narrow size distributions,and the mass fraction of 50%Ni was more appropriate.The electrochemical impedance spectra of Ni-YSZ prepared by ultrasonic co-precipitation method was compared with Ni-YSZ prepared by mechanical mixing method,it showed that the former had smaller resistance than the latter.
WANG Shu-feng, LI Hui-qi, CHI Jing, LI Min, CHAI Lu, XU Hui. Microstructure and Crystallization Mechanism of Composite WC Alloy Produced by Plasma In-situ Metallurgy[J]. Journal of Materials Engineering, 2011, 0(8): 72-76.
The composite WC alloy was prepared by plasma in-situ metallurgy.The microstructure,phases,hardness and crystallization mechanism were examined separately by SEM,XRD,hardness-testing devices.The results show that the microstructure of the sample is uniform,and the hard phases are WC,W2C,Fe3W3C and a small amount Cr7C3.The average hardness(HRA) of the alloy is 84.2,the average hardness HV0.1 of the WC grains in the alloy is 2636.In the molten pool,dissolution and precipitation are the nucleation mechanism of the WC crystals.The growth pattern of WC is a layer-by-layer fashion by means of multi-layer stacking of(0001) basal along 〈0001〉 orientation to form a triangular prism shape,the largest WC grains can may grow to more than 70μm.
CHEN Gui-qing, FU Gao-sheng, YAN Wen-duan, CHENG Chao-zeng, ZOU Ze-chang. Experimental Research on Dynamic Recrystallization of 3003 Aluminum Alloy[J]. Journal of Materials Engineering, 2011, 0(8): 77-81.
The 3003 aluminum alloy was deformed by isothermal compression in the range of deformation temperature 300-500℃ at strain rate 0.01-10.0s-1 using Gleeble-1500 thermal simulator.The strain-hardening rate could be obtained from true stress-true strain curves,and the recrystallization average grain size was measured using the intercept method.The results show that the critical strain εc increases with parameter Z increasing,the critical conditions for onset of dynamic recrystallization(DRX) is ε>εc=7.28×10-5Z0.1661.The average recrystallization grain size increases as deformation temperature increases and the strain rate decreases,which can be described as lndave=-0.0824lnZ+4.9532.The investigated alloy is sensitive to positive strain rate under the experimental conditions.The true stress increases as the deformation temperature decreases and the strain rate increases.The peak stress increases with the average recrystallization grain size decreasing,which meets with the law of Hall-Petch:lnσm=-0.9378lndave+6.5232.
LIU Jian-ye, CHEN Juan, LIU Hua-shi, WANG Dong-zhi, GE He-yi. Preparation of Vinyl Ester Resin Sizing Agent for Carbon Fiber by Phase Inversion Emulsification[J]. Journal of Materials Engineering, 2011, 0(8): 82-86,92.
Through phase inversion emulsification method emulsion type vinyl ester resin sizing agent for carbon fiber was prepared using vinyl ester resin and epoxy terminated butadiene-acrylonitrile oligomer.Effects of type and mass ratio of emulsifiers,emulsification temperature,shear rate and solvents on properties of emulsion were investigated by centrifugal sedimentation analysis,particle size analysis and Zeta potential analysis.The results showed that the optimal emulsion was obtained when the mass ratio of polyoxyethylene nonylphenol phosphoric ammonium and polyoxyethylene castor oil was 3:1,mass ratio of emulsifiers was 10%,emulsification temperature was 50℃,shear rate was 10000r/min and mass ratio of diluent styrene was 50%.The average particle size of the emulsion was 0.068μm.Centrifugal sedimentation mass fraction was 8.67%.Zeta potential and surface tension of the emulsion were 53.24mV and 32mN·m-1,respectively.A sudden increase of conductivity appeared at phase inversion point,then the conductivity reached equilibrium.
ZHANG Xiao-hong, QIAO Ying-jie. Progress in Fiber-enhanced Composite Materials for Stealth Applications[J]. Journal of Materials Engineering, 2011, 0(8): 87-92.
Stealth technology is indispensable in the modern military equipment and stealth materials is important substantial foundation of modern stealth technology.In this work,the domestic and foreign development and status of fiber reinforced stealth materials with different components are summarized on the base of mechanical and electromagnetic properties.The possible direction about stealth technology was also pointed.
ZHANG Xiao-wen, LI Lei, YAN Yue. Research Progress of Plasma Display Panel Filter[J]. Journal of Materials Engineering, 2011, 0(8): 93-98.
The advantages and disadvantages of the plasma display panel(PDP) were reviewed,and the research process of PDP filter was analyzed.The functions of the filter including elctromagnetic interference(EMI) shielding,near infrared(NIR) blocking,neon cut(Ne-cut) and anti-reflection(AR) were introduced respectively.The study and application for the materials and preparation of the functionalized films were carried on.
