NING Yong-quan, YAO Ze-kun, GUO Hong-zhen. Microstructure and Mechanical Properties of IN718 Alloy by Near-isothermal Forging[J]. Journal of Materials Engineering, 2010, 0(11): 1-4.
Near-isothermal forging were carried out on IN718 alloy to study the effect of parameters,i.e.temperature,deformation and strain rate,on microstructure and mechanical properties.Mechanical properties were affected by the deformation temperature since the grain coarsening with increasing temperature.And it should be pointed that the mechanical property was significantly effected by the shape and volume of interstitial phase.Acerose phase with suitable in volume was contributed to optimal property.Growth up of the interstitial phase was related to dislocation density and temperature.Under full-precipitation condition,acerose phase grew up to short-stick-shape.But under non-full-precipitation condition,acerose phase only precipitated at the final stage of the deformation and reserved acerose shape.
WANG Hong-lei, ZHOU Xin-gui, YU Hai-jiao, ZHAO Shuang, LUO Zheng. Study on the Properties of SiCf/SiC Composites Fabricated by Vapor Silicon Infiltration[J]. Journal of Materials Engineering, 2010, 0(11): 5-7,93.
Two different carbon-base SiCf/C were prepared by chemical vapor deposit and resin polymer impregnation and pyrolysis,then the KD-1 SiCf/SiC composites were fabricated by vapor silicon infiltration using homebred KD-1 SiCf as reinforcement,and the microstructure and mechanical properties of SiCf/SiC composites were investigated.The results show that the fracture toughness of SiCf/SiC composites fabricated though different carbon-base SiCf/C are very different,the values are 12.9MPa.m1/2 and 2.0MPa.m1/2 respectively.The density and mechanical properties of SiCf/SiC composites fabricated though SiCf/C of higher porosity were better than the SiCf/C of lower porosity,which were prepared by Phenolic resin polymer impregnation and pyrolysis.
ZHANG Ming-jun, LUO Yu-shi, XIAO Cheng-bo, TANG Ding-zhong, WU Zhong-tang. Effect of Withdrawing Rate on Microstructure of Single Crystal Superalloy DD6[J]. Journal of Materials Engineering, 2010, 0(11): 8-10,16.
The effect of withdrawing rate on microstructure of single crystal superalloy DD6 was investigated.The results show that,with the decreasing of withdrawing rate,the primary dendrite arm spacing increases,the size of γ′phase in the dendrite core and in the interdendrite increases slightly,the volume fraction of γ-γ′eutetic decreases,and the segregation of main elements decreases.
XU Ying, WANG Juan, DOU Yu-bo. Study of Al-N Co-doped-type ZnO Films and Their Properties[J]. Journal of Materials Engineering, 2010, 0(11): 11-16.
Al-N co-doped ZnO thin films was prepared by sol-gel method.Al-N co-doped actual situation was studied by the X-ray photoelectron spectroscopy detection.The influence of Al-N co-doped doping concentration,film thickness and heat treatment temperature on the crystallization properties,micro-morphology and optical properties of this kind of films were studied,using by X-ray diffractometer,filed emission stereoscan,spectral photometer,Hall admeasuring apparatus.The results indicated that the crystallization properties,micro-morphology and optical and electrical properties of Al-N doped ZnO films were best on the condition that when the sol density was 0.5mol/L,Al-N doped density was 10%,the heat treatment temperature was 600℃,the luminousness and electrical resistivity also Hall mobility ratio was best.
LIU Hui-min, LIU Li, XU Ping. Study on Reheating Process of 7075+1.7TiC Al Alloy in Semi-solid State[J]. Journal of Materials Engineering, 2010, 0(11): 17-20,25.
The microstructures of in-situ reactive spray formed 7075+1.7%TiC Al alloys at semi-solid state were observed using SEM.The grain sizes were measured using a mean linear intercept method and the effect of in-situ TiC particles on grain growth in the two-phase(liquid + solid) region of 7075 Al alloy were analyzed.It was shown that the grain growth was very slow at 580℃ and when the reheating temperature was up to 600℃,the grain growth velocity was increased gradually.The average grain sizes were 14μm and 20μm at 580℃and 600℃ for 60min.when the reheating temperature was up to 610℃,the grain growth velocity was increased evidently,and part reheating was appeared.The average grain sizes were 53μm at 620℃ for 30min,which indicates that in-situ reactive spray formed 7075+1.7%TiC Al alloy can keep fine and equiaxed characteristic,and meet the requirement of thixoforming on microstructure of alloy.
WANG Zhen-bang, CHEN Zhi-gang, LIU Cheng-bao, DUAN Xiao-tao, CHEN Hong, FU Meng. Preparation of Expanded Graphite-based Carbon/Carbon Composites and Its Adsorption Properties on Phenol[J]. Journal of Materials Engineering, 2010, 0(11): 21-25.
Expanded graphite-based carbon/carbon composites(EGCs) were prepared by impregnation of expanded graphite(EG) in H3PO4/sucrose solution.The textural,structural characteristics of the composites were investigated by scanning electron microscopy(SEM) and nitrogen adsorption method.The results indicated that the worm-like particles were partly covered by pyrolytic carbons while the large open spaces among entangled worm-like particles were scarcely any,most of the activation carbon(ACs) covered the surface of interior pores of EGCs in the form of thin carbon layer with the thickness of 87nm.In the best condition of Xp=0.9,350℃ and 120min,the obtained sample had the highest surface area of 1948 m2/g.The phenol removal capabilities of EGCs were 24.8% higher than that of activated carbons which were prepared in the same condition.
ZHOU Xu, WU Jiang-yu, LI Yan, JIANG Tie-kuns. Microwave-assisted Synthesis of Polyamidoamine Dendrimer Core[J]. Journal of Materials Engineering, 2010, 0(11): 26-29.
Aiming to improve the synthetic efficiency of polyamidoamine dendrimer,the triethanolamine-based dendrimer core was prepared through microwave-assisted synthesis procedure.The molecule structure of each product was characterized by Infrared Spectra(IR) and Hydrogen Nuclear Magnetic Resonance(1H NMR).The effect of the power of microwave on the product yield was investigated and the synthetic conditions were optimized for each step of reaction.After 30min,60min and 50min of microwave-assisted reaction,the yield of the product was 72.5%,73.8%,and 69.3% for trinitrile,triester,and triamine,respectively.
HU Tian-yun, DENG Yun-lai, TANG Chang-ping, ZHANG Xin-ming. Study on Heterogeneity of Microstructures and Properties of As-extruded EW83 Magnesium Alloy Plate[J]. Journal of Materials Engineering, 2010, 0(11): 30-34,82.
Heterogeneity of microstructure and mechanical properties of the as-extruded EW83 magnesium alloy plate was investigated by means of OM,SEM,EDS,XRD and hardness testing.It is found that heterogenous evolution of the microstructures are affected by the recrystalliZation and precipitation particle.In the edge of the plate,because of the grain refining effects resulted from the increase of the realZ parameter(heavy shear deformation and quick decrease of temperature),the hindering motion of the grain growth by the precipitation particles,and the recrystalliZation by particles stimulated nucleation(PSN),the measured grain siZe is half of the predicted one by the mean parameter(Z).In the middle of the plate,because of the grain coarsening effects caused by the decrease of the real Z parameter,static recrystalliZation,the measured grain siZe is twice times as the predicted one by the Z.The hardness value of the specimens cutting from the edge of the as-F plate increases by 5% than those of the middle one.However,after aged at 215℃,the peak hardness of the specimens cutting from the middle of the as-T6 plate increases by 10% than that of the edge one.
ZHANG Jing-feng, TIAN Yi-guang, LIN Shi-e, WENG Xue-jun, LIU Hai-tao. Effect of Properties of SBR/N330 Nanocomposites for N330 Partially Replaced by Pyrophyllite Based Modified Composite Powder[J]. Journal of Materials Engineering, 2010, 0(11): 35-38,56.
The Styrene-butadiene Rubber(SBR)/N330/ Pyrophyllite Based Modified Composite Nanopowder(PBMCN) nanocomposites were prepared by melt mixing procedure.The dispersion,mechanical and vulcanization behaviors for the effect of PBMCN on SBR/N330/PBMCN nanocomposites were studied.The results show that the PBMCN has favorable dispersibility in the matrix of SBR/N330/PBMCN nanocomposites.The tensile strength,elongation at break and vulcanization behavior are improved in SBR/N330/PBMCN nanocomposites when N330 is replaced by PBMCN for 20% mass fraction.The reinforcement mechanism of PBMCN in SBR/N330/PBMCN nanocomposites was investigated.
LIU Yong-sheng, ZHANG Jin-cang, GU Min-an, YU Li-ming, YANG Jing-jing, GAO Tian, YANG Zheng-long, PENG Lin. Microstructure and Frequency Properties in Fe-based Alloys[J]. Journal of Materials Engineering, 2010, 0(11): 39-42.
Fe-based alloys Fe-Ni and Fe-Co,with a nanostructure,are fabricated by high-energy milling,and their structure and frequency properties are studied.The particle size of samples with body-centered cubic grain structure is 0.5-5μm,while that of samples with body-centered cubic and face-centered cubic grain structure is 5-20μm.The Co-doping increases the threshold frequency for Fe-Co.The pure Fe and Fe-Ni samples have a resonant characteristic in the real component curve of A.C.permeability,while the Co containing ones show a relaxant behavior.Fe-7.69%Ni or Fe-7.69%Co(atom fraction),the real component of ac permeability reaches a maximum.At high frequency,the imaginary component of A.C.permeability increases with decreasing of Co-doping for Fe-Co,and the minimum of imaginary component shifts to higher frequency with Co increasing.The minimum of imaginary component also shifts to higher frequency with Ni increasing for Fe-Ni,and pure Fe has a lower imaginary component than doping samples.
HU Jian-ping, CAI Ji-zhe, ZHAO Yan, LIU Jian-hua. Effects of Hygrothermal Environment on Properties of Nomex Sandwich Composite[J]. Journal of Materials Engineering, 2010, 0(11): 43-47.
After conditioning in the hygrothermal environment,the moisture absorbing plot was recorded and mechanical and dielectric properties of different kinds of Nomex sandwich structure composites were investigated in the dry and wet conditions.The results show that different samples had distinct moisture absorbing performance in the hygrothermal environment.And the hygrothermal circumstance will bring negative effects on the mechanical properties of the sandwich structure facing and core.After comparing among these materials,two kinds of facings have the similar moisture absorbing properties,and the epoxy/NH-1-72 composite has the relatively better conditioning resistance performances in the mechanical aspect.In addition,the hygrothermal environment will also decrease the dielectric properties of the sandwich structure,and the epoxy/NH-1-48 sample has the best dielectric properties conditioning resistance for its lowest core density.
CHENG Yan-hai, ZHU Zhen-cai, HAN Zheng-tong, ZOU Yong. Effect of Heat Treatment on the Structure and Hardness of the Electroless Ni-P Deposits[J]. Journal of Materials Engineering, 2010, 0(11): 48-51.
The deposits of electroless Ni-P with different nanocrystalline phase were prepared by electroless plating on mild steel substrate.The deposits were heat treated at 200℃ and 400℃ for 1h in an argon atmosphere,respectively.The effects of the heat treatment on the structure and hardness of the deposits were investigated and compared against the properties of the as-deposited samples by means of EPMA,XRD,hardness tester.The experimental results showed that the Ni-P deposits changed from amorphous to nanocrystalline with the increasing of nanocrystalline phase,thus increased the hardness of the deposits.The hardness of the amorphous and the co-existence became increased due to the precipitation of Ni3P at 200℃ heat treatment.The hardness of nanocrystalline deposit became decreased as the results of relaxation when being heat treated at 200℃ for 1h.The hardness of the deposits increased considerably due to the precipitation of dispersed hard Ni3P intermetallic compounds and nickel phase in the nickel matrix when being heat treated at 400℃ for 1h.The diffraction peaks strength of nanocrystalline in the XRD pattern had greater increase than that of the amorphous and the co-existence.However,the hardness of amorphous deposit increased greatly as the result of the amorphous deposit had more precipitation of Ni3P than that of nanocrystalline and the co-existence.
HU Hui-e, KONG Xiao-dong, CHEN De-bin, HU Yu-long. Microstructure Characterization of 7050 Aluminum Alloy During High Temperature Deformation[J]. Journal of Materials Engineering, 2010, 0(11): 52-56.
Dynamic recrystallization and dynamic recovery in 7050 aluminum alloy during high temperature deformation have been investigated by tensile tests conducted at 460℃ and strain rates of 1.0×10-4s-1 and 0.1s-1.It is shown that the increase in the average misorientation angle is proportional to the increase in the true strain during high temperature deformation of the 7050 aluminum alloy.The grain size of the 7050 aluminum alloy increases with increasing true strain with the strain rates of 1.0×10-4s-1 and 0.1s-1,respectively.While the aspect ratio of grains remains unchanged after high temperature deformation at 460℃/1.0×10-4s-1;and it increases with the true strain during deformation at 460℃/0.1s-1.Microstructure results show that continuous dynamic recrystallization and dynamic recovery are the softening mechanisms when strain rates are 1.0×10-4s-1 and 0.1s-1,respectively.The continuous increase of the average misorientation angle during continuous dynamic recrystallization is attributed to the migration of subgrain boundaries and the absorption of dislocations into grain boundaries.
CHENG Yao, HE Lin, ZHOU YUAN-kang, YAN JIAN-wei. Study on Friction Property of Palygorskite Resin Composites with PTW Modified by Stearic Acid[J]. Journal of Materials Engineering, 2010, 0(11): 57-59,65.
Effect of potassium titanate whiskers(K2O.6TIO2,PTW)modified by stearic acid was studied.Compounded friction materials with PTW and palygorskite and studied enhancement mechanism of composite materials.Found out that it is not uniformly dispersive to the composites with 15% PTW additive amount,the change of frictional coefficient is not great.Composites with 13% PTW additive amount and below the amount of it had little effect to frictional coefficient of composites.The composites with 10% PTW additive amount have a lowest wear rate,wear resistance increased 27% to improve the wear ability significantly,especially on high temperature phase above 250℃,improved significantly.
HE Cheng-han, LIU Ping-gui, HE Li-hua, SONG Jiang-xuan, LI Qi-fang. Morphologies and Thermal Properties of Alkoxysilane Terminated Polyurethane/Epoxy Resin Composites[J]. Journal of Materials Engineering, 2010, 0(11): 60-65.
Two kinds of alkoxysilane terminated urethane oligomers(PUSi),polytetramethyleneoxide glycol(PTMEG) urethane oligomer(PTSi) and polycaprolactone(PCL) urethane oligomer(PLSi),were directly synthesized via reacting diols of PTMEG and PCL with isocyanatopropyltriethoxysilane(ICPTES),respectively.PUSi/epoxy composites were prepared via sol-gel process and the reaction of amine curing agent and epoxy resin.The structure of PTSi and PLSi were characterized by FTIR.The morphology and thermal properties of the composites with different ratio of PLSi and PTSi were investigated with SEM,DMTA and TGA analysis.The results showed that a "sea-island" phase structure was formed in PUSi/epoxy composites,and that the compatibility between PUSi and epoxy was improved with adding PLSi.And also,when the mass ratio of PLSi and PTSi was 1:1,the PUSi/epoxy system had a highest temperature value at 5% mass loss,reaching to 275℃,an increase of 100℃ when compared with that of neat amine-cured epoxy resin.
WANG Zhang-zhong, ZHOU Heng-zhi, BA Zhi-xin, BAI Yun-qiang. Infiltration and Deposition of Electroless Planting Ni-P Deposits at Fatigue Crack Tip of 45 Steels Under Alternate Loads[J]. Journal of Materials Engineering, 2010, 0(11): 66-68,87.
The infiltration and deposition behavior of electroless planting Ni-P deposits at the fatigue crack tip of 45 steels under alternate loads was investigated firstly.The influence of the electroless planting Ni-P deposits on the crack propagation rates was analysed.The morphology and compositions of the chemical deposition were charactered by SEM,EDS and XRD,respectively.The crack growth rates of the samples with and without chemical deposition were compared.The results indicate that the deposition behavior of electroless planting Ni-P alloy obviously occurres at the fatigue crack tip,which effectively reduces the crack growth rates.
SUN Zhi-hua, LIU Ming, GUO Da-peng, GUO Meng-qiu, LU Feng, TAO Chun-hu. Study on Tribological Behavior of Microarc Oxidation Ceramic Coating of Aluminum Alloy with Different Thickness[J]. Journal of Materials Engineering, 2010, 0(11): 69-73,78.
The tribological performance of the microarc coatings with different thickness was evaluated using pin-on-disk tribometer,and surface morphology,cross-section structure and abrasive morphology before and after the test were analyzed by scanning electron microscope(SEM),and phase constituents were studied by X-ray diffraction(XRD).The results show that the thickness on the cross section becomes same and the film/substrate interface even with MAO time.The results of XRD reveal that the content of γ-Al2O3 in the ceramic coatings decreases,while α-Al2O3 increases with oxidation time,and so the average hardness increases with the oxidation time.The abrasive wear mass loss and wear rate increase with the oxidation time for the unpolished MAO films,while that decrease for the polished MAO films.The abrasive trace shows scales,grooves and there are not any cracks observed.
ZHANG Xiao-yun, TANG Zhi-hui, SUN Zhi-hua, YU Bo. Galvanic Corrosion and Protection Between Titanium Alloy and Other Materials[J]. Journal of Materials Engineering, 2010, 0(11): 74-78.
The susceptibility of galvanic corrosion on titanium alloy coupled with other materials were summarized.The result showed that the galvanic corrosion between titanium alloy and aluminum alloys or structural steel was serious,it is necessary to protect aluminum alloys and structural steel when it is coupled with titanium alloy.There was no galvanic corrosion between titanium alloy and stainless steel in room temperature,but it is possible different result in high temperature.There was no galvanic corrosion between titanium alloy and composites.The current density of couples could be decreased by surface treatment to aluminum alloys and structural steels,and decreased greatly by spraying paint and sealants after surface treatment.
HUANG Jun, WU Hong-yan, BI Qiang, ZHANG Ping-ze, JIANG Yun-dong. Microstructure and Corrosion Resistance of Ni-Cr Alloyed Layer Formed by Double Glow Plasma Surface Metallurgy[J]. Journal of Materials Engineering, 2010, 0(11): 79-82.
The W-Mo alloyed layer was deposited on surface of Q235 steel by double glow plasma surface metallurgy.The microstructures,composition and corrosion resistance of the alloyed layer were investigated.The results showed that the Ni-Cr alloyed layer obtained was well bonded to the substrate.The nickel and chromium content in the alloyed layer decreased gradually from surface to substrate,the thickness of the alloyed layer was 30μm and the phase of the alloyed layer was Ni2.9Cr0.7Fe0.36.The polarization curve indicated that the corrosion resistance of the specimen was improved evidently after Ni-Crco-diffusion treated.The protection efficiency of the Ni-Cr alloyed layer was 99.7468%,while the porosity of the alloyed layer was only 0.2%.
LEI Wei-ning, LIU Wei-qiao, QU Ning-song, WANG Jiang-tao. The Progress of Electroplating Technology in Supercritical Fluids[J]. Journal of Materials Engineering, 2010, 0(11): 83-87.
The characteristics of supercritical fluids and their new electroplating methods were analyzed.The investigation progress of the effects of surfactants and carbon dioxide concentration on conducive emulsion in supercritical carbon dioxide electroplating were summarized including process parameters of temperature and pressure.The latest researches of the high-performance nano-materials preparation in supercritical fluids electroplating were presented,and the potential developments of this technology in the future were expected.
LENG Jian-cheng, XU Min-qiang, XING Hai-yan. Research Progress of Metal Magnetic Memory Testing Technique in Ferromagnetic Components[J]. Journal of Materials Engineering, 2010, 0(11): 88-93.
Metal magnetic memory technique has potentials to detect early failure,such as stress concentration and fatigue damage of ferromagnetic components.The paper summarizes recent advances in the developments of magnetic memory technique,from mechanism study,basic experiments to influence factors on detection signals and its engineering application,and discusses some questions in theory and practical applications.The characteristics and future research directions of metal magnetic memory technique are also presented on the basis of the current research status at home and abroad.
CHEN Lei, XU Zhi-wei, LI Jia-lu, ZHANG Liu-fei, CHEN Li, WU Xiao-qing, SUN Ying, CHEN Guang-wei. Structure and Bullet-proof Mechanism of Ballistic Composites[J]. Journal of Materials Engineering, 2010, 0(11): 94-100.
The interaction mechanisms of bomb block and composites are discussed,and the energy-absorbing means and failure mode of composites are analyzed in the penetration process of bomb block.The structural design of bullet-proof composite was put forward.The influence of single-fiber properties,fabric structure,resin,matrix content and interface strength on the bullet-proof performance is investigated.It is expected that this paper is beneficial to the structural design of bullet-proof composites.
