ZHANG Xiao-li, FENG Yao-rong, ZHUANG Chuan-jing, ZHAO Wen-zhen, HUO Chun-yong. Study on Effective Particle Size of High Grade Pipeline Steels and Relationship Between CVN[J]. Journal of Materials Engineering, 2008, 0(7): 1-5.
The parameters which affect toughness of the high grade pipeline steels were studied by using EBSD.It was shown that the grains had higher grain boundary orientation than 15° would be helpful to toughness of materials,when grain boundary orientation higher than 35°,it was useless to the parameters study of pipeline steels.The effective particle size,the frequency distribution of grain boundary orientation and the ratio of higher grain boundary to low grain boundary were important parameters in high grade pipeline study;The finer the grain size,the smaller the effective particle size,and the higher the frequency of grains boundary of higher than 50°,would effectively lead to the excellent toughness of high grade pipeline steels.
WANG Kuang-fei, GUO Jing-jie, LI Chang-yun, XIONG Yan-cai, FU Heng-zhi. Numerical Simulation of Effect of Thermal Gradient on Structure Evolution During Directional Solidification of Ti-Al Alloy[J]. Journal of Materials Engineering, 2008, 0(7): 6-11.
The structure evolution of Ti-Al alloy during directional solidification was simulated to investigate the effects of the applied temperature gradient by applying a solute diffusion controlled solidification model with Cellular Automation(CA),and the results have showed that with increasing thermal gradient,the morphology of the interface varies from dendrite to the mixed structure of cell and dendrite to cell to fine cell,finally to superfine cell,which accordingly decrease the dendrite arm spacing.In addition,the high thermal gradient directional solidification also results in reduction in the enrichment of solute at interface,the solute trapping at interface and refinement of cells.
ZHOU Chang-rong, LIU Xin-yu. Study of Y2O3 Doped(Bi0.5Na0.5)0.94Ba0.06TiO3 Lead-free Piezoelectric Ceramics[J]. Journal of Materials Engineering, 2008, 0(7): 12-14.
Effect of Y2O3 addition on the crystal structure and electrical properties of lead-free piezoelectric ceramics(Bi0.5Na0.5)0.94Ba0.06TiO3was investigated.X-ray diffraction showed that all samples possess single perovskite structure.The temperature dependence of dielectric constant of Y2O3 doped BNBT6 samples indicated obvious relaxor characteristics and the relaxor behavior was more strongly with increasing Y2O3 addition.The maximum value of d33=137 pC/N,kp=0.30 and kt=0.47 were obtained at 0.5% and 0.1% Y2O3 addition,respectively.
LI Yun, WANG Liu-ding. Influences of CeO2 Doping on Optical Properties of TiO2 Film[J]. Journal of Materials Engineering, 2008, 0(7): 15-17.
TiO2 thin film was successfully prepared with electron beam evaporation.The influences of refractive index,transmittance and band gap on doped TiO2 film were studied.The results indicate that adaptive Ce-doped improves the refractive index of TiO2 film;doping CeO2 makes band gap value reducing from 3.27eV to 2.5eV,resulting in the absorption edge shifting from 380nm to 495nm.In this way,more solar energy is utilized.
DU Feng-shan, DENG Shao-kui, YAN Liang, DAI Sheng-long. Study on Overheat Temperature of Ingot and High Temperature Plasticity of 2E12 Aluminum Alloy[J]. Journal of Materials Engineering, 2008, 0(7): 18-21.
The overburnt temperature of 2E12 Aluminum alloy ingot studied by means of microst-ructure analysis and DSC.The homogenization temperature and heat treatment temperature were obtained.Doing experimentation on the mechanical behavior and high temperature pressing of ingot,the graph of mechanical behavior at different temperatures was obtained, providing gist for rolling technics.According to experimentation results,the overburnt temperature of 2E12 was 507℃;the plasticity of this alloy was very good,and the rolling temperature range was 300-460℃.
ZHANG Zeng-zhi, ZHANG Da-wei, XU Hai-feng. Effect of Fly Ash on Clay's Characteristic of Water Conductivity[J]. Journal of Materials Engineering, 2008, 0(7): 22-26.
A new type technique of material which was used to plant trees in drought areas was developed.Joining the different comparison or modified fly ash by different reagent in clay,can increase its surface areas and improve conductivity function.This can ameliorate the soil's characteristic of water conductivity by capillarity in drought areas,solve its problem of lacking of water,and recycle scrap fly ash.The chosen samples were analyzed by BET surface area measurement,scanning electron microscope and thermal multi-analyzer.The results showed that the water conductivity of samples was best when fly ash was 20% in clay.Modified fly ash can improve its water conductivity function by using hydrochloric acid or sodium carbonate,and the effect was best when the concentration of hydrochloric acid was 0.3mol/L or sodium carbonate was 0.5mol/L.
SUN Jun-long, LIU Chang-xia, HE Shi-long. Microstructures and Mechanical Properties of B4C/Al2O3/TiC Composite[J]. Journal of Materials Engineering, 2008, 0(7): 27-29.
B4C/Al2O3/TiC composites were prepared by hot pressing with different content of Al2O3 and TiC as additives.The effect of TiC content on microstructures and mechanical properties of the composites has been studied.The toughening mechanisms of B4C/Al2O3/TiC composites are discussed.The experiment results showed that TiB2 formed by the in-situ reaction between B4C and TiC during hot pressing,and resulted in a B4C/Al2O3/TiC composite with high relatively density and enhanced mechanical properties compared to B4C/Al2O3 composite.The sintering temperature was lowered from 2150℃ for B4C/Al2O3 composite to 1900℃ for B4C/Al2O3/TiC composite. The toughening mechanisms of B4C/Al2O3/TiC composites are mainly crack deflection and crack pining.
WANG Qiu-na, LIU Xin-hua, LIU Xue-feng, XIE Jian-xin. Study on Annealing Process and Microstructure and Properties of Cold-drawing Copper Cladding Aluminum Thin Wires[J]. Journal of Materials Engineering, 2008, 0(7): 30-35.
The appropriate annealing process for cold-drawing copper cladding aluminum wire was studied.The variations of mechanical properties,microstructure of copper sheaths and diffusion thickness of copper cladding aluminum wires with annealing process were investigated.The results show that the proper annealing process for copper cladding aluminum wire is 300℃×60min.At an annealing temperature below 200℃,a recovery of microstructure occurs in copper sheaths,the strength of the copper cladding aluminum wire decreases dramatically from 361MPa to 236MPa and the elongation drops a little compared with unannealed wires.Annealed at 300℃,the recrystallization of microstructure in copper sheath is fully completed,the strength of the copper cladding aluminum wire drops to 152MPa and the elongation achieves maximum value 16.3%.The grain size of copper sheath grows up and intermetallic phases are formed at interface as annealing temperature reaches 400℃,while the elongation of material decreases.The diffusion thickness increases as annealing temperature and time increase.When the annealing temperature is lower than 300℃,with the increase of annealing time,diffusion thickness increases slowly.When the annealing temperature is higher than 350℃,the diffusion thickness increases quickly as the annealing time prolongs.With the diffusion thickness increasing,the elongation shows a trend that it increases at the beginning and then decreases.The critical diffusion thickness of copper cladding aluminum wire is 2μm,when the material possesses optimum mechanical properties.
LUO Yu-shi, HAN Mei, LI Jia-rong, Zhao Jin-qian, LIU Shi-zhong, TANG Ding-zhong. A Heat Treatment for Improving Creep Properties of DD3 Single Crystal Superalloy[J]. Journal of Materials Engineering, 2008, 0(7): 36-39.
A optimized heat treatment for improving creep properties of DD3 single crystal superalloy was introduced. According to the results of differential thermal analysis and physicochemical phase analysis to casting and standard heat treatment samples,a optimized heat treatment regime was created.The optimized heat treatment characterized with that increased the solution heat-treatment temperature in excess of 1260℃ followed by two aging heat treatment.The microstructures and mechanical properties were evaluated for samples given both the standard and the modified heat treatment.The optimized heat treatment resulted in optimized microstructure and increased levels of chemical homogeneity,and also remarkably improved creep properties.
KANG Jin-xing, ZHAO Wen-zhen, XU Ying-ge, SUN Li-ming. Effect of Electrodeposited Technology Parameter on Hardness of Bulk Nanocrystalline Nickel[J]. Journal of Materials Engineering, 2008, 0(7): 40-42,46.
Bulk nanocrystalline nickel was fabricated using the method of direct current deposition by changing the concentrations of the special additive C7H4NO3SNa·2H2O,current density and bath temperature.The microstructure of electrodeposits was evaluated by means of high-resolution transmission electron microscopy(HRTEM). The micro-hardness of electrodeposits was measured.Law of micro-hardness varying was studied.The results show that the bulk nanocrystalline nickel coatings of uniform structure are fabricated by changing parameters of technology.The micro-hardness increases with the increasing of the concentrations of the additive C7H4NO3SNa·2H2O.The micro-hardness increases with increasing of the current density.The micro-hardness almost doesn't increase with increasing of the current density between 700A·m-2 and 1100A·m-2.The micro-hardness reduces with increasing of the temperature.
WANG Yan-chen, ZHENG Liang. Effect of Process on Microstructure of Cast Ni-based Superalloy K403[J]. Journal of Materials Engineering, 2008, 0(7): 43-46.
The effect of solidification cooling rate and heat treatment on the microstructure of cast Ni-based superalloy K403 were investigated in.The results indicate that employing the shell temperature of 880℃ with back sand or 950℃ single-shell at the pouring temperature of 1460℃ can obtain fine γ' phase.Aging treatment at 900℃/16h and 980℃/5h for K403 can achieve fine M6C和M23C6 carbides which distributed at the grain boundaries.
FAN Xiao-hua, TANG Yi-ke, HOU Chang-jun, FAN Ying. Effect of Heat Treatment Temperature on Structure and Hydrogen-sensing Properties of Pt-WO3 Thin Films[J]. Journal of Materials Engineering, 2008, 0(7): 47-50.
Pt-WO3 thin films have been prepared with Sol-Gel method and DC reactive magnetron sputtering method.After annealed in ambient N2 at 100-500℃,the microstructure and surface morphology of the films were analysed with XRD and AFM.The effect of annealing temperature and content of catalyzer(Pt) on the structure and hydrogen-sensing properties were examined.The results showed that the Pt-WO3 thin films which annealed below 400℃ are amorphous and have good hydrogen-sensing properties;The films which annealed over 400℃ are crystalline and have bad hydrogen-sensing properties;The permeated ray rate and hydrogen-sensitivity of the films decreased with annealed temperature;The amount of Pt has effect on the film's hydrogen-sensing property,when the content is 5%(mass fraction) Pt,the Pt-WO3 thin film has good hydrogen-sensing property.
ZHANG Wei, CHEN Dong-mei. Heat Resistance Behavior of Hot Dip Aluminized Steel with Rare Earths[J]. Journal of Materials Engineering, 2008, 0(7): 51-54.
The pure aluminized coating and La-aluminized coating on 20 carbons steel was prepared by hot dip aluminizing method,respectively.The oxidation resistances and microstructures of the coatings were investigated after diffusion treatment at 900℃ for 6h.The results show that,the thickness of the surface coating of the hot dip La-aluminized specimens decrease by about 25%-35% than that of the hot dip pure aluminized specimens.After diffusion treatment,the oxidation kinetics curve of pure aluminized coating accords with a parabola growth rule before 40h and then presents a linear growth rule with a higher oxidation rate after 40h.The oxidation kinetic curve of La-aluminized coating obeys a parabola growth rule during the whole oxidation and its mass increase is less than that of pure aluminized coating.La addition can restrain the formation and aggregation of voids and subsequently improve the resistances to oxidation and spalling.The mechanism of the La effect on the heat resistance behavior of hot dip aluminized steel is also discussed.
LI Song-mei, WANG Yan-qing, LIU Jian-hua, LIANG Xin. Influence of cladosporium on Corrosion Behavior of Steel A3[J]. Journal of Materials Engineering, 2008, 0(7): 55-58.
The influence of cladosporium on the corrosion behaviors of Steel A3 was studied using open circuit potential(Eocp),Electrochemical Impedance Spectroscopy(EIS) and Scanning Electron Microscopy(SEM).The results of electrochemical test indicated that the electrochemical behaviors of steel A3 were influenced by the present of cladosporium.Eocp of the systems with and without bacteria all shifted positively at first,and then negatively during the 7 days of immersion.After 2 days and 7 days of immersion,Eocp in the system with cladosporium was more negative than that in the sterile medium on the same day,which showing a higher electrochemical activity on the metal surface.On the 15th day of immersion,Eocp in the system without bacteria going to steady while Eocp in the system with bacteria shifted to positive about 25mV.The results of EIS were consistent with the results of Eocp on the 2nd and 7th day.Samples in the system with cladosporium reached a lower resistance value than in the sterile medium on the 15th day.SEM results showed that crazing occurred on steel A3 in the sterile medium while serious pitting corrosion occurred on the metal surface in the system with cladosporium;the present of cladosporium changed the corrosion morphology and accelerated the corrosion of steel A3.
ZHANG Zi-jun, CHENG Xu-dong, LI Qi-lian, DENG Fei-fei, GAO Zhong-bao, CHEN Ming, MAO Fang, YANG Zhang-fu. Effect of Precursor's Concentration on Microstructure of ZrO2 Nanostructure Coatings Deposited by Solution-precursor Plasma Spray[J]. Journal of Materials Engineering, 2008, 0(7): 59-63.
Different concentration solution were prepared with ZrOCl2 ·8H2O,as a precursor,ZrO2 coating were deposited by solution-precursor plasma spray.ZrO 2 coatings were analyzed by scanning electron microscopy and X-ray diffraction.The results shows that there are no layer structure,which are always present in the conventional APS coatings,but the round hole with the consistent size is uniformly distributed in the matrix of the coating.Crystal structure is changed with the concentration of precursor solution,too thin or too thick will does bad effect to the coating.The results shows that 0.8mol/L is better for the coatings.The ZrO2 coatings showed a mean grain size within nanometer that is smaller than conventional coating grain size.
LI Chong , HE Xiao-dong, LI Qing-fen. Mechanical Properties of Ti3AlC2 Ceramics Prepared by SHS/PHIP[J]. Journal of Materials Engineering, 2008, 0(7): 64-67.
The flexural strength,the fracture toughness,Vickers-hardness and compressive properties of Ti3AlC2 ceramics prepared by SHS/PHIP were tested.The experimental results showed that the flexural strength at room temperature was 330.8MPa,the fracture toughness was 5.7MPa·m1/2 and Vickers-hardness was 2.9GPa.The resistance of deformation of Ti3AlC2 ceramics was 823MPa at room temperature.With deformation temperature increment,the resistance of deformation of Ti3AlC2 ceramics was reduced,and its plastic behavior was improved.Ti3AlC2 ceramics prepared by SHS/PHIP had excellent workability because of low Vickers-hardness and good mechanical properties.
LI Zhi-bin, WU Ya-ting, DENG Yi-da, HU Wen-bin. Effect of Size on Optical Absorption Property of Hollow Nickel Spheres[J]. Journal of Materials Engineering, 2008, 0(7): 68-71.
Hollow Ni spheres with different diameters have been synthesized by the autocatalytic reduction method.The morphologies,size distribution and optical absorption property of the hollow Ni spheres were investigated,indicating that when the hollow Ni spheres became smaller,the optical absorption intensity is obviously increased in ultraviolet -near infrared region.Additionally,in ultraviolet region,the optical absorption property of the hollow Ni spheres in nanoscale is distinctly different from that of the hollow Ni spheres with big diameter.On the whole,in the total measured wavelength region,the optical absorption property of the hollow Ni spheres with small diameter show high intensity and low amplitude of fluctuation,while the optical absorption property of the hollow Ni spheres with big diameter show high amplitude of fluctuation.
ZHANG Zeng-zhi, ZHANG Li-mei, MA Xiang-dong, YANG Chun-wei, HUANG Hua, ZHANG Yu-xiao. Controllable Water-releasing Mechanism of Water-releasedly Coated Fiber[J]. Journal of Materials Engineering, 2008, 0(7): 72-75.
A water-releasedly coated fiber was presented.The natural plant fiber was coated with mixed colloid composed of sop organic macromolecule(PVA) and ultra-fine montmorillonite grain.The micro-appearance of the coated fiber was described by the environment scanning electronmicroscope.The desorption of the mixed colloid was detected by thermogravimetry.The water-releasing characteristics with various soil moisture were analyzed by fast watere-quipment.The water-releasing mechanism was proposed. The results showed that the montmorillonite grain were distributed evenly throughout PVA.At the side of high flow of wateron of the fiber,PVA swelled to transfer water.At the other side,PVA shrinked so that the montmorillonite grain join to form the transferring channels due to the low flow of water,by which,the water-releasing mechanism that water were trasferred because of different water potential caused by discordant energy barriers was realized.
WANG Hai-peng, CHEN Xin-wen, LI Xiao-jun, MA Li-ting, SU Bin. Tensile Strength Distribution of Glass Fiber Reinforced Composites at Different Temperatures[J]. Journal of Materials Engineering, 2008, 0(7): 76-78.
The tensile strength of glass fiber reinforced composites was tested using tensile method at different temperatures and the strength distribution was studied on simple linear regression. The tensile strength at different temperatures was fitted,furthermore,the tensile strength at lower temperature was predicted,and the predicted results are basically in agreement with the experimental data.The present work established a referrence for the application of glass fiber reinforced composites.
YANG Chun-wei, HU Xin-guo, ZHANG Liang, DAI Chang-song. Study of Functionalization on Multi-wall Carbon Nanotubes by Ultrasound[J]. Journal of Materials Engineering, 2008, 0(7): 79-82,87.
Functionalization of multi-wall carbon nanotubes(MWCNTs) was important for application in catalytic realm.MWCNT was purified during the sonochemical treatment with nitric and sulfuric acids.At the same time,MWCNT was shortened and its ports were opened.MWCNT was also decorated by a great lot of oxygen-contained function groups on the surface and ports.It was good for the active elements to deposit on the surface uniformly.Transmission Electron Microscope(TEM),Raman spectrum,Infrared spectrum(IR) was used to characterize the degree of surface functionalization and coverage.The PtRu catalyst which was supported with treated MWCNT was also studied in the way of Cyclic Voltammetry(CV) and Electrochemical Impedance Spectroscopy(EIS),and a better methanol electrooxidization activity was gained.
ZHAO Jian-guo, GUO Yong, FENG Feng, ZHANG Su-fang, WANG Hai-qing. Research Progress in Coaxial Nanocable Materials[J]. Journal of Materials Engineering, 2008, 0(7): 83-87.
Nanocable materials have been the focus and emphasis due to their particular electric,optoelectronic,magnetic properties,and geometric structure.Recent progress in nanocable materials is reviewed briefly.The structure of nanocable materials and the development of synthetic technology,including arc discharge,chemical vapor deposition and capillarity methods,are described in detail.The prospects for application and future development are outlined.Nanocable materials have paramount importance for the practical application of nano-material-based equipments.
