LI Xiao-fei, ZHANG Qi, XIANG Min. The Influence of the Conductivity of the Carbon Fiber/Epoxy Composite by Immersion[J]. Journal of Materials Engineering, 2009, 0(2): 1-5.
Because the corrosion behavior of composite is related with the environmental factors,the selection of the test parameters depends on the serving environment mostly.The immersion corrosion tests and mechanical property tests were carried out.By the comparison,it could be seen that the existence of the salt and the change of the test temperature affected the water Absorption rate of the sample remarkably.Along with immersion,the electric resistance tests and mechanical property tests have also been made.The results showed that water and corrosive medium could cause extensive corrosion,and consequently cause the change of the morphology and electric resistance of the samples obviously.
JIANG Ri-peng, LI Xiao-qian, ZHANG Li-hua, ZHANG Xue, WU Yu, XIE En-hua. Research on the Solidification Structure Refining Laws of Pure Aluminum Under Different Methods of Ultrasonic Vibration[J]. Journal of Materials Engineering, 2009, 0(2): 6-10.
Industrial aluminum melt was treated by ultrasonic with two methods: applying static continuous vibration and dynamic intermittent vibration.And the solidification structure refining laws was analyzed according to the theory of cavitation and acoustic effects.The results indicate that solidification structures are both refined to different extents by two ways.Under the condition of continuous vibrating,structure refining effects are diverse with different ultrasonic powers.Structure refining effect is best and the grain size is smallest when applying vibrating power 170W.Under the condition of intermittent vibrating,when ultrasonic power varies from small to large,structure refinement is more perfect.Better structure can be obtained if treating time and temperature selected correctly during the process of applying ultrasonic vibration for different time at the diverse temperatures.
KUANG Shuang, KANG Yong-lin, YU hao, LIU Ren-dong. Strain-hardening Characteristics of a Cold Rolled C-Si-Mn Dual Phase Steel[J]. Journal of Materials Engineering, 2009, 0(2): 11-14,18.
A cold rolled dual phase steel with C-Si-Mn alloy system was piloted.Strain-hardening characteristics of the trial steel were investigated by using mechanical test,microstructure observation and modified C-J analytical method.The results show that there exist two stages in the strain-hardening process of dual phase steel.The strain-hardening ability is strong in the first stage while weak in the second stage.There is a transition strain existing between the two stages.Strain-hardening abilities of both stages strengthen with the increase of martensite volume fraction(Vm) when Vm is less than 16%,but weaken with the increase of Vm when Vm exceeds 16%.The transition strain monotonically decreases with the increase of Vm.The difference of elastic-plastic behaviors between ferrite and martensite in dual phase steel is the main reason to induce two stage hardening characteristics.The increase of Vm could improve strengthening effects,but the plastic resistance of martensite decreases due to the dilution of carbon content in martensite.Only when the strengthening effect caused by the increase of Vm is more than the weakening effect caused by the decrease of carbon content in martensite,strain-hardening ability of dual phase steel could increase.
LI Ping, LI Li, TAN Jia-long, HAO Jing-yan, WANG Qing. The Relativity Between Elastic Moduli and Cluster Structure of Cu-based Metallic Glasses in Cu-Zr-Al Systems[J]. Journal of Materials Engineering, 2009, 0(2): 15-18.
The longitudinal and shear ultrasonic velocities of Cu54Zr42.5Al3.5 and Cu58.1Zr35.9Al6 bulk metallic glasses(BMGs) with cluster structures Cu8Zr5 and Cu6Zr5 respectively were measured by water-immersion focusing method.The correlation between the calculated elastic moduli and the microstructure of BMGs characterized by the chemical short range order of cluster structures was analyzed.The results indicate that the regularity of velocities and the elastic moduli is Cu54Zr42.5Al3.558.1Zr35.9Al6,moreover,the regularity keeps identical with the chemical short range order of cluster structures.
ZHAO Cai, JIANG Hai-tao, TANG Di, ZHAO Song-shan, CHENG Zhi-song. Research on Deformation Mechanism and Relationship Between Microstructure and Properties of Quenching and Partitioning Steel[J]. Journal of Materials Engineering, 2009, 0(2): 19-23.
Metallurgical microstructure and fine structure were experimentally investigated on the thermo-mechanical simulator(Gleeble3800).Lath martensite and retained austenite were obtained in Si-Mn Q&P steel containing C,Si,Mn through Q&P process.A large amount of thin films of retained austennite distributed between the lathes of the martensite was detected by means of TEM.The volume fraction of the residual retained austenite based on X-ray diffraction was analyzed quantitatively by the software programmed with VC6.0++.The mechanical properties generated in steels by the Q&P treatment are studied by MTS electronic tensile testing machine.It is verified that Q&P steel possesses a good combination of strength and plasticity due to its fine microstructure.It exhibited high ultimate tensile strength(exceeding 1000MPa) and fine elongation of 25%.The fracture mechanism of Q&P steel was clarified based on examination to the fracture surface of specimens with scanning electronic microscope.The results show that fracture morphology of the low carbon Si-Mn Q&P steel is a dimple pattern with features of plastic fracture.The retained austennite play a role of phase transformation induced by plastic deformation.
GUO Tong-xiu, LIU De-lin, YU Yang. Preparation of High Silicon Nickel-copper Alloy NCu30-4-2-1 Extrusion Bars[J]. Journal of Materials Engineering, 2009, 0(2): 24-28.
The variation regularity of the strength and the plasticity of high silicon nickel-copper alloy NCu30-4-2-1 influenced by temperature was investigated by short-time high temperature tensile tests.Hot compression tests of as-cast nickel-copper alloy were performed under the condition of different temperatures and different strain rates with a Gleeble-1500 thermal mechanical simulator.The regularity of the flow stress influenced by temperature and strain rate was researched,and the effects of temperature and strain rate on the deformed microstructure were studied.Based on the test results,the appropriate extruding temperature and extruding velocity were determined.As a result,the mechanical properties of extrusion bars were greatly improved.
ZHOU Li-min, LUO Tai-an, HUANG Qun-wu, LIU Zhi-rong. Photocatalytic Activity of Different Shape-controlled TiO2 Nanoparticles Toward Methyl Orange[J]. Journal of Materials Engineering, 2009, 0(2): 29-33.
Different morphologies of TiO2 nanoparticles were prepared through the sol-gel method using titanium butoxide and titanium chloride as precursors.The shapes of TiO2 nanoparticles were controlled by using sodium dodecyl benzene sulfonate(DBS),sodium dodecyl sulfate(SDS) and hydroxypropyl methyl cellulose(HPMCS) as shape-controlled agent.The photocatclytic activity of the TiO2 nanoparticles was evaluated using methyl orange as model compound.The XRD results indicated that the TiO2 nanoparticles calcined at 500℃ had the anatase phase.The UV-vis Absorption spectra suggested that the TiO2 nanoparticles shaped by surfactants showed a red shift and lower band gap energy.TiO2 nanoparticles with different shapes showed different photocatalytic activities.The cubic TiO2 nanoparticles shaped by DBS had a higher photocatclytic activity than other samples.TiO2 nanoparticles calcined at 600℃ had a highest photocatalytic activity toward methyl orange.
LI You-sheng, DENG Jian-xin, ZHANG Hui, LI Jian-feng. Oxidation Resistance of Cemented Carbide Tools[J]. Journal of Materials Engineering, 2009, 0(2): 34-37,42.
Four kinds of cemented carbide tools(YG6,YG6X,YS8 and YT15) were selected,and using electric stove,the cutting tools were heated and heat-preserved to make oxidation experiment.The results of trial are as follows.In the oxidation experiment,WC that is a component of cutting tools is partially oxidized to WO3,the element of Co is oxidized to Co3O4.However,TiC is very stabile in tool material,when the temperature is up to 1300K,TiO2 that is the oxidation of TiC is found.Cutting tool materials which contain TiC have better oxidation resistance than those which don’t contain TiC,similarly,tool materials that have smaller grain size often have better oxidation resistance.The oxidation resistance’s sequence of four kinds of cutting tools is as follows: YS8>YT15>YG6X>YG6.
REN Ji-wen, PENG Bei, ZHANG Hong-hai, LIU Sheng. Research on the Sintering Processing of the Yttria Stabilized Zirconia Nano Powders[J]. Journal of Materials Engineering, 2009, 0(2): 38-42.
The sintering process of 8%(mole fraction,the same below) yttria stabilized zirconia(8YSZ) nano powders was investigated.The density of 8YSZ ceramics was measured according to Archimedes’ principle.The line shrinkage was obtained by measuring the size of 8YSZ ceramics before and after sintering.The microstructure of 8YSZ ceramics was observed by SEM.The densification process of the 8YSZ ceramics during sintering was discussed.The influence of the sintering process on the density and grain size was analyzed.The optimum sintering process of 8YSZ nano powders is adopting two steps sintering which is first heated at 1500℃ and then holding at 1450℃ for 4h.By this process the 8YSZ electrolyte with high relative density(98%) and small grain size(<3μm) was obtained.In addition to,the influence of the grain size of powder on sintering performance was investigated.The result shows that the start sintering temperature of nano powder is lower than micron powder and adopting powder with bimodal particle sizes is helpful to improve the sintering performance.
XIONG Ji-chun, LI Jia-rong, HAN Mei, LIU Shi-zhong. Effects of Pouring Temperature on the Solidification Microstructure of Single Crystal Superalloy DD6[J]. Journal of Materials Engineering, 2009, 0(2): 43-46.
The effects of pouring temperature on the solidification microstructures of single crystal superalloy DD6 were investigated.The results show that with the decrease of pouring temperature,the primary dendrite arm spacing increases,the size of γ′ phase in the dendrite core and in the interdendrite increases slightly;And with the decrease of pouring temperature,the size of the γ-γ′ eutectic increases,but the volume fraction of γ-γ′ eutectic decreases,the segregation ratio of main elements decreases obviously.
LIU Tian-mo, LIU Yu, LU Li-wei, LI Nan, HE Shun, SUN Chao-yong. Kinetics of Recrystallization of Cold Forging AZ31 Magnesium Alloy[J]. Journal of Materials Engineering, 2009, 0(2): 47-50.
The annealing process was made under different temperature and holding time to the cold forging AZ31 magnesium alloy with different deformation ratio.The results show that the relationship between annealing time and volume fraction of the static recrystallization can be described by the JMAK equation by the investigation of microstructure evolution and kinetics analysis of static recrystallization.Based on the experiment data,the activation energy was calculated to be about 53.5kJ/mol,and the time for static recrystallization completion was calculated,which could be a reference for the techniques of annealing treatment.
ZHANG Ying-hui, ZHAO Hong-jin, KANG Yong-lin. Microstructure and Mechanical Properties of 600MPa TRIP Steel Produced by TSCR Process[J]. Journal of Materials Engineering, 2009, 0(2): 51-53,57.
C-Si-Mn TRIP steel was prepared by TSCR process in laboratory.The results of tensile experiment indicated that the ultimate tensile strength was 630MPa,yield strength was 430 MPa,elongation was 29.1%.The results also indicated that the microstructure was composed with ferrite,bainite and retained austenite.The counting of quantitative colour metallography showed that retained austenite volume fraction was about 6.6%.
REN Hui-lan, NING Jian-guo, Wang Ying. Acoustic Emission Characterization of Ceramic Fracture[J]. Journal of Materials Engineering, 2009, 0(2): 54-57.
Advanced multi-channels acoustic emission system was used to study the fracture process of ceramic subjected by three-point-bending.Compared with the acoustic emission(AE) signals from none-edge-notched and single-edge-notched specimen of ceramic,the pre-made notch played important role on the damage and fracture of ceramic.The results were shown that amplitude of AE changing with loading time reflected the damage state of ceramic,such as the nucleation,the growth,the interaction,the coalesce of micro-cracks and occurrence of macro-cracks.It is indicated that AE technique has been an important means in the studies of the damage and fracture to materials.
SONG Yan-jiang, HUANG Li-jian, ZHU Peng, WANG Xiao-dong, HUANG Pei. Friction and Wear of Coupling Agent Treated Glass Fiber Modified Polyimide Composites[J]. Journal of Materials Engineering, 2009, 0(2): 58-62.
The glass fibers(GF) were treated by different silane coupling agents,the effects of content and size of GF on mechanical properties and tribology properties of TPI composites were investigated.The worn surfaces were analyzed by SEM.The results indicate that mechanical properties and tribology properties of TPI composites filled with treated GF are higher than those with untreated GF,and the KH550 is most favorable.The wear rate of TPI composites increased with the higher GF content,and the friction coefficient is slightly higher than pure TPI.The wear rate and friction coefficient of TPI composites reduced with the GF size decreased.SEM photograph of fracture surface revealed that there is best interface bonding between KH550 treated GF and TPI matrix.The wear mechanism of the TPI composites is characterized by remarkable adhesion and abrasive wear.
LIU Cui-xia, YANG Yan-qing, ZHANG Rong-jun, REN Xiao-xia. Measurement and Evaluation of the Tensile Strength of CVD SiC Fibers with Carbon Coating[J]. Journal of Materials Engineering, 2009, 0(2): 63-66,73.
Tensile strength of SiC fibers uncoated and coated carbon by Chemical Vapour Deposition(CVD) method was tested at room temperature.Weibull distribution function is found to describe the distribution of the fibers’ tensile strength excellently.The results show that the Weibull modulus and the average value of tensile strength about the SiC fibers coated carbon were both higher obviously than that of the SiC uncoated carbon.With the increase of gauge length and stain velocity,the average value of SiC fibers’ tensile strength decrease and the Weibull modulus keep constant.Moreover,through analyzing the fracture of SiC fibers,it is found that a brittle fracture of the fibers can be seen clearly and the method of carbon coating can decrease the surface’s defect,so the tensile strength of SiC fibers can be increased effectively.
XU Zhen-hua, MU Ren-de, CAO Xue-qiang, HE Li-min. Study of the Interdiffusion Behavior Between NiCrAlYSi Coating and Ni-based Superalloy Substrate[J]. Journal of Materials Engineering, 2009, 0(2): 67-73.
The NiCrAlYSi coating was deposited on Ni-based superalloy DZ125 by Arc-Ion Plating(AIP).The concentration profiles of Al and Cr in the samples with different oxidation time were analyzed.The interdiffusion coefficients of Al and Cr were calculated by using Boltzmann(Matano method and the fitted curves at 1373K for the oxidation time of 0.5,2h and 5h.The results indicate that the interdiffusion coefficients of Al and Cr increase with the atomic contents of Al and Cr under the same temperature.Along with the increment of the oxidation time,the interdiffusion coefficient of Al increases first with the variety of atomic content and then basically keeps constant,while the interdiffusion coefficient of Cr gradually decreases.The elemental interdiffusion between the coating and the substrate occurs as Al and Cr diffuse inward from the coating to the substrate and Ni,Co,Mo,Ti and W diffuse outward from the substrate to the coating,but the contents of Mo and Ti in the coating are comparatively less.According to the elements interdiffusion behavior,the coating composition would tend to become more uniformly distributed.
SHEN Yue-song, ZHU She-min, QIU Tai. Preparation of Mesoporous Titania-coating for Monolithic DeNOx Catalyst Supporter[J]. Journal of Materials Engineering, 2009, 0(2): 74-78.
A high specific surface titania-coating for monolithic DeNOx catalyst supporter was prepared by three sol-gel methods.Mesoporous titanium dioxide loading of honeycomb ceramics coped by 5% in mass nitric acid solution was investigated.The experimental results and the microscopic analysis of SEM,XRD and BET showed that the sol chelated by glacial acetic acid had a long sol time,its sol glutinosity was easy for honeycomb coating and its titanium loading capacity was the biggest.Titania-coating particles on surface dispersed uniformly and the specific surface of TiO2 in anatase corresponded to 71.52m2/g,which provides a promising basis of making monolithic honeycomb catalyst of DeNOx in China.
CAO Ning, LI Mu-sen, LI He-sheng. Study Progress of the Preparation Optimization and Characterization of Plasma-sprayed Hydroxyapatite Coatings[J]. Journal of Materials Engineering, 2009, 0(2): 79-84.
The latest development of plasma-sprayed hydroxyapatite coatings on biomedical materials has been summarized.Its content refers to promotion of plasma-sprayed technology,characterization of coating’s phase structure and mechanical properties,numerical simulation of coating process and biological estimation.On the basis of introduction above,the development trend of plasma-sprayed hydroxyapatite coatings is also proposed.
