ZHU Zi-xin, LIU Yan, XU Bin-shi, MA Shi-ning, ZHANG Wei. Influence of Heat Treatment on Microstructure and Wear Behavior of Fe-Al/WC Composite Coatings[J]. Journal of Materials Engineering, 2004, 0(7): 3-5.
An experimental study had been carried out to investigate the influence of heat treatment at 300,450,550,650,800℃ on the microstructure and sliding wear behavior of Fe-Al/WC intermetallic composite coatings produced by high velocity arc spraying(HVAS) and cored wires. The Fe2W2C and Fe6W6C precipitated phases was found in heat treated coatings. After heat treated at 450～650℃, the dispersion strengthening of Fe2W2C and Fe6W6C and distortion of lattice due to some Fe3Al transformation into FeAl led to rise of microhardness of the coatings.Increasing the microhardness through heat treatment would improve the sliding-wear resistance of the Fe-Al/WC composite coatings.
SU Tie-jian, GAO Shu-juan, LI Shu-kui, WANG Fu-chi, ZHANG Zhao-hui. Characteristics of Adiabatic Shear Bands in Several Steels with Different Hardness and Thermal Conductivity[J]. Journal of Materials Engineering, 2004, 0(7): 6-9.
Research was conducted on characteristics of adiabatic shear bands(ASBs) in several steels by contained exploding cylinder technology. It is shown that the high hardness and low thermal conductivity promote the formation of transformed ASBs, and the deformed ASBs will form if low hardness and high thermal conductivity are involved; for steel with both high hardness and thermal conductivity, the transformed ASBs will transform into deformed ones, due to that the fast heat conduction from high temperature ASBs results in rapid temperature rise around and thus decreasing the hardness.
XU Qian-gang, TANG Jian-xin, LU Feng, WU Xue-ren. Formation and Effect of the Oxidation Mixed Zone in TGO Beneath a Thermal Barrier Coating Prepared by EB-PVD[J]. Journal of Materials Engineering, 2004, 0(7): 10-13,17.
The cyclic oxidation behavior of EB-PVD TBCs between 1150℃ and 30℃ was investigated. The formation process of YSZ-Al2O3 mixed zone in TGO and its effect on the growth of TGO and failure of TBCs were analyzed. Outward growth of TGO and YSZ fine grains zone were two important requirements for the formation of YSZ-Al2O3 mixed zone. The effect of YSZ-Al2O3 mixed zone on the failure of TBCs lies with the accelerated growth of TGO and cracks easily formed in the oxide mixed zone.
BEI Yi-ling, LIU Xiao-xuan, ZHANG Xing-hong, WU Guang-guo. Study on the Microstructures and Thermal Stability of MA/ATMP Copolymers[J]. Journal of Materials Engineering, 2004, 0(7): 14-17.
MA/ATMP copolymers were prepared by the photo-induced solution copolymerization at various initial monomer ratios in toluene. The compositions and the sequence distributions of MA/ATMP copolymers were characterized with 1H-NMR. On this basis, the thermal stability of the copolymers with different microstructures and the glass transition temperature(Tg) were measured. Thus the splitting decomposition temperature of the groups in the copolymers and the glass state changes of the material as well as the relationship between these changes and the composition of the copolymer chains and the sequence distribution are confirmed.
YANG Zhi-hua, JIA De-chang, ZHOU Yu, SHI Peng-yuan, SONG Cheng-bin. Preparation and Oxidation Resistance of SiCsf/SiC-BN Composites[J]. Journal of Materials Engineering, 2004, 0(7): 18-22.
SiC-BN composites, reinforced by SiC short fibers, were fabricated via in-situ synthetic reaction(SiCsf/SiC-BN). These oxidation kinetics were analyzed and calculated from 800℃ to 1200℃. Oxidation resistance of SiCsf/SiC-BN composites had been analyzed from 800℃ to 1200℃. The results show that the in situ synthesis, which used Si3N4, B4C and carbon as reactants, could take place to form the matrix of composites. SiC and BN are oxidized to form SiO2 and B2O3 at high temperature. The SiO2 and B2O3 react to form stable borosilicates glass which can decrease rate of oxidation.
HU Chun-xia, WU You-shi, WEI Hui-ying. Study on the Effects of Rh Doping on Microstructure and Properties of Tin Dioxide Nanocrystallines[J]. Journal of Materials Engineering, 2004, 0(7): 23-26,31.
Beginning with SnCl2, equable dispersed and stable SnO2 and Rh-doping SnO2 nanocrystallines were synthesized by the compound-precursor chemical method. The XRD and HRTEM analyses show that prepared Rh doping SnO2 nanocrystallines has samller particle radius than the undoping ones. Besides, there are enwrapped structures around the Rh doping SnO2 particles. According to discussions on the UV-Vis curves of SnO2 and Rh-doping SnO2 nanocrystallines, it is clear that the excitonic absorption and the band-gap edge absorption all moved toward smaller wavelength, namely ‘red shift’.
ZHU Li-qun, LIU Hui-cong, DU Yan-bin. Study of Stainless Steel's Phosphate Oxidation Disposaland Advanced Film Prepared by Sol-gel Method[J]. Journal of Materials Engineering, 2004, 0(7): 27-31.
The phosphate oxidation film was obtained on the surface of stainless steel, subsequently the sol-gel film was produced, and the effect of accelerant to the film was researched. The anti-corrosion performance of the film was assessed through salt-spray test, damp heat test, brine marinating test and anode polarization curve, and the effect on mechanical property was studied through drawing-extending test. The results show that the stainless steel material has good anti-corrosion performance after phosphate oxidation, and accelerant improved its anti-corrosion performance, meanwhile its mechanical property is not affected, the sol-gel treatment following greatly enhances its corrosion performance.
WAN Hong, SI Yong-min. Study on the Bending Property of TbDyFe Magnetostrictive Cantilever[J]. Journal of Materials Engineering, 2004, 0(7): 32-34,39.
The bending property of TbDyFe magnetostrictive film cantilever was studied by finite-element modeling(FEM). The calculated results show that the deflection is direct proportion to the film thickness when the film thickness is less than one tenth of that of the substrate, which is totally comparable to the results proposed by other researchers, and the deflection reaches to the maximum value when the film thickness is half of the substrate. The modeling also reveals that the increase of the elastic modulus ratio between the film and the substrate can improve the deflection value of the cantilever obviously.
LI Qiang, LI Dian-zhong, QIAN Bai-nian. Modeling Microstructure Evolution of Al-7%Si During Solidification Process by Cellular Automaton Method[J]. Journal of Materials Engineering, 2004, 0(7): 35-39.
A continuum method was employed to deal with the discontinuous physical properties in the solid/liquid interface. Furthermore, in order to precisely calculate the solute concentration in each element, the distance changing between the two neighbor elements due to solidification process was considered. Moreover, a random noise was inputted to describe the random disturbance in the local interface region. Using cellular automaton method, Al-7%(mass fraction)Si binary alloy ingot was simulated. The simulated results show that this method can reflect the microstructure evolution during solidification, as well as the inter-grain micro-segregation appearing.
ZENG Wei, TAN Song-ting. Properties of the Nickel-coated PET Fiber Filled the Epoxy Resin Composite[J]. Journal of Materials Engineering, 2004, 0(7): 40-43.
The conductive composites were prepared by blending PET/Ni fibers, obtained by means of ultrasonic electroless nickel, with epoxy resin. The morphology structure and conductivity of the fiber had been studied. The composites' conductivity,the effects of nickel-coated PET fiber contents on electrical, electromagnetic shielding and mechanical properties had been studied also.The results indicate that the composites have excellent conductivity and electromagnetic shielding capability when a low content(1%～5%, mass fraction,the same below) nickel-coated PET fiber is filled, and the mechanical properties of the composites are improved when fiber content is 3%.
CHENG Yan, CAI Wei, LI Hong-tao, ZHENG Yu-feng, ZHAO Lian-cheng. Effects of Annealing Treatment on the Microstructure of Tantalum Coatings on TiNi Alloys[J]. Journal of Materials Engineering, 2004, 0(7): 44-46,50.
Multi-arc ion plating technique was employed to coat TiNi shape memeory alloy with tantalum about 3 μm. Then the as-deposited samples were annealed at different temperature in vacuum atmosphere. The results of XRD show that the film as-deposited is composed of a metastable tetragonal β-phase which can transform into α-phase tantalum after annealing at 700, 800, 900℃ for 1h respectively. TEM observations show that thin nano-structured Ta layers are obtained in the as-deposited samples. Mixture of microcrystallite(about 40nm) and large-size crystal(about 150nm) α-phase tantalum were formed in the film after annealing at 700℃. When annealed at 900℃, the film is mainly composed of dominantly uniform large-size α-phase tantalum.
QIAO Xiao-jing, YU Ren-guang, REN Hui, WANG Chang-fu. Comparison of Intercalated Carbon Fibers with Copper-plated Carbon Fibers[J]. Journal of Materials Engineering, 2004, 0(7): 47-50.
The intercalation compound was synthesized by mixed molten salt with carbon fibers as host and CuCl2 as guest. It is found that the microcrystal in the intercalation compound becomes more when its structure is analyzed by X-ray diffraction. The surface morphology, characters of thermal stability and IR extinction of the intercalated carbon fibers are compared with the plated carbon fibers. The results show that both intercalated carbon fibers and copper-plated fibers can interfere infrared from 8 to 14μm, and the average mass extinction coefficient of the latter is slightly more than the former. When the decomposed percentage of the sample is 5%, the temperature of the intercalated carbon fibers is higher than that of the copper-plated, which is 660.6℃ and 545℃, respectively.
LI Guo-rong, HUANG Yong-qiu, PAN Ding. Formation Mechanism of Spherical Pyrolytic Carbon During theCVD Process of an n-heptane/carbon Tetrachloride Mixture[J]. Journal of Materials Engineering, 2004, 0(7): 51-54,63.
Spherical pyrolytic carbon was made by control of technical conditions. It is approved that condensation-polymerization mechanism exists in the CVD process by analyzing the intermediates qualitatively. The effects of temperature on morphology and deposition process of PyC are explained by using thermodynamics and the principle of the nuclei-growth of crystals.
HUANG Zu-xiong, WU Wei. Application of Carbon Nanotubes for the Wave-absorbedStealthy Composites Based on Polymer[J]. Journal of Materials Engineering, 2004, 0(7): 55-59.
Particular attention is paid to promoting the novel stealthy materials' properties, such as strong absorption, wide frequency, light mass, thinness, multifunction, compatible absorption for infrared and microwave, and other excellent properties. Since there are eminent properties in polymer and predominant electromagnetic wave-absorption property in CNTs, it is an effective way to use them for the exploitation of new polymer/carbon nanotubes wave-absorbing composites. Based on the stealthy mechanism of wave-absorbed materials, the character of electromagnetic wave-absorption is discussed. Recent research progress of carbon nanotubes/polymer wave-absorbed stealthy composites is introduced especially and technical problems in the future are also suggested.
WANG Lei, YAN De-sheng, JIANG Zhi-min, RONG Li-jian. Research and Development of Ni-Ti-Nb Shape Memory Alloy Pipe-joint with Wide Hysteresis[J]. Journal of Materials Engineering, 2004, 0(7): 60-63.
The development of NiTiNb shape memory alloys with wide hysteresis and the working principle of shape memory alloy pipe-joint are reviewed. The characteristic of preparation,principle of structure-design and technology of pre-deformation of the NiTiNb shape memory alloy pipe-joints are discussed. The development of small-scale shape memory alloy pipe-joints applied in pneumatic circuit is introduced.
