YANG Hong-wei, WANG Ying-chun, CAO Chuan-bao, HE Yong-qing. Hydro-thermal Synthesis and Gas Sensing Properties of Zinc Oxide Nanorods-microspheres[J]. Journal of Materials Engineering, 2007, 0(2): 3-6,10.
ZnO nanorods-microspheres organized by zinc oxide nanorods and sub-micrometer rods were prepared in a hydro-thermal method, using zinc powder as the starting material. Their structure and morphology were characterized by XRD and SEM analyses, and their gas sensitivities were measured. The results show that the zinc oxide nanorods-microspheres doped with nickel can enhance their selectivity to ethanol and gasoline.
ZHANG Yu-xian, WANG Hong. A New Constitutive Relationship Between Stress and Strain for Materials[J]. Journal of Materials Engineering, 2007, 0(2): 7-10.
In order to effectively study the residual stresses of auto-frettagea super high pressure vessel, this paper first offers a new model of the constitutive relationship of stress-strain. Through the strict mathematical testimony, this model is shown to be closer to the actual working condition of the steel applied in auto-frettagea super high pressure vessel than other models; then this paper describes how this model is established by taking some material as examples, and analyzes the model’s error. This example illustrates the feasibility and the reliability of solving the new constitutive relationship for stress and strain based on general tensile curves. The model also has theoretical signification and engineering practical value to a certain extent.
XIONG Lan-tian, JIN Hai-bo, CAO Mao-sheng, WANG Fu-chi, LI Zhong-ping. Study on Evolution Behavior of Damp-proofing Admixture Under Ablation in SiO2/SiO2 Composites[J]. Journal of Materials Engineering, 2007, 0(2): 11-14.
The evolution behavior of damp-proofing admixture (organic silicon resin) in silicon dioxide composites with ablation processing is investigated. It is demonstrated that silicon carbide is generated through complex chemical reactions such as decomposing, cementite, and carbothermal reduction. The experimental results are discussed based on FTIR, DAT/TG, XRD, SEM and SEAD analysis results, and the formation process and growth kinetics are explained then.
ZHAO Qing, YUAN Xue-tao, DU Nan. Corrosion Behavior of Sintered NdFeB in HNO3 and HF Mixing Solution[J]. Journal of Materials Engineering, 2007, 0(2): 15-18.
Corrosion behavior and damage micrography of sintered NdFeB in HNO3+HF mixing solution were studied by means of SEM, EDS, E-t curve, Tafel curve and EIS. The results show that the general corrosions in mixing solution mainly take place on the matrix phase and intergranular Nd-rich phase, after that the Nd-rich phase still netted-distributed on grain boundary.
GU Zhuo-ming, GU Cai-xiang, FAN Shao-qing. Study on Lubricating Oils Containing Mixtures Additives of Nano-CaCO3 and Nano-Cu[J]. Journal of Materials Engineering, 2007, 0(2): 19-22.
The Nano-CaCO3 and nano-Cu particles was selected as mixtures additives of lubricating oils. The suitable surfactants were selected,and lubricating oils with mixures of nanoparticles of CaCO3 and Cu were prepared. Their tribological properties were tested in four-ball tribotester. The surface morphology of wear scar were examined by scanning electron microscope(SEM). The nanoparticles morphology and distribution on worn surfaces were analyzed by atomic force microscope(AFM) and scanning electron microscope(SEM). The research results show that,the optimal additive volume and proportion of nanoparticles are: mass fraction of mixures of nanoparticles of CaCO3 and Cu is 0.6%,and their mass fraction ratio is 1:1;and this lubricating oil has excellent tribological properties.The optimum tribological properties of mixures of nanoparticles of CaCO3 and Cu in lubricating oils may be related with existing states of nanoparticles on surfaces.
YAO Lan, LI Wen-bin, QIU Yi-ping. Study on Tensile and Dielectric Properties of Three-dimensional Orthogonal Woven Composites[J]. Journal of Materials Engineering, 2007, 0(2): 23-25,29.
Development of three-dimensional (3D) fiber composites overcomes the weaknesses of traditional laminated structures with in-plane and through-thickness dimensions are suitable for various industrial applications.The tensile and dielectric properties of 3D orthogonal woven aramid-glass fiber/epoxy composites have been investigated experimentally. Five different structures of the composites were designed with the different layer numbers of aramid and glass fiber in the preforms. The test results showed that the pure aramid/epoxy composite has the highest specific tensile strength and specific modulus. For the dielectric properties, the composites in which the more volume of glass fiber is included, the more constant the dielectric properties are. For the different applications, hybrid method of different fiber can exert different advantages of fibers.
WANG Xue-ming, LI Guo-li, LI Ai-ju. Effects of Silane Pretreatment for Low Carbon Steels on the Adhesive Strength of Polyethylene Coatings[J]. Journal of Materials Engineering, 2007, 0(2): 26-29.
Polyethylene coatings were fabricated on low carbon steels after pretreatment with KH-550, KH-560 and KBM-7103, respectively. This paper focused on the effect of silane pretreatments on the property of coatings by testing the adhesive strength and thermal shock resistance of coatings. The results indicated that the adhesive strength of coatings after substrates pretreated with KH-560 was higher than those with sandpaper grinding and blasting by 40.3%, 13.2%, respectively, and that KH-550 and KBM-7103 had less effect on the adhesive strength. The optimum concentration of 5% (volume fraction) and hydrolysis time of 48h for KH-560 pretreatments can contribute to a better adhesive strength. Moreover, the adhesive strength obtained by the associated pretreatment of blasting and KH-560 decreased much less than that of other pretreatments after the thermal shock resistance.
LIU Zhi-wei, YANG Dong-fang, ZHAO Hui-you. Preparation and Microwave Characterization of Ultrafine Nitriding Magnetic Particles[J]. Journal of Materials Engineering, 2007, 0(2): 30-33,38.
The nitriding particles were synthesized by the solid-gas reaction method. The effects of the process parameters on the products were investigated to obtain more Fe4N. The results show that more Fe4N (45%) is gained at 360℃, 3h. When nitriding time keeps constant, the permeability increases as increasing temperatures, while the permittivity reverses. When nitriding temperature keeps constant, the permittivity fall as increasing the time. The absorbing properties become better by mean of dispersion and the reflectivity reach -11.18 at 11.67GHz.
ZHAO Shu-guo, YUAN Xiao-guang, LI Sheng, YU Hai-peng. Microstructure and Properties of Semi-solid Formed Al-Si-Fe Alloy[J]. Journal of Materials Engineering, 2007, 0(2): 34-38.
A kind of Al-17Si-5Fe-3Mn-4Cu-2Ni-1Mg alloy has been prepared by semi-solid forming technology. The microstructure of the alloy has been analyzed, the mechanical properties of the alloy have been tested, and the wear-resisting property and the wear failure form of the alloy have been studied by wear test. The results show that the second phase in the semi-solid formed alloy become fine and spherical, and its distribution is homogeneous. The ultimate tensile strength and elongation of the alloy are 239.6MPa and 2.0% respectively. Under the condition of dry and lubrication friction wear at 150℃, the mass loss are 30.78% and 3.09% that of as cast 390 aluminum alloy respectively.
LIN Li, NIE Ying, LI Xi-meng. Ultrasonic Testing of Thin Layered Structure Based on Marr Wavelet Analysis[J]. Journal of Materials Engineering, 2007, 0(2): 39-41,45.
It is difficult to recognize the overlapping signal of the front and bottom echoes from the thin layer structure. In order to measure the thickness of the thin layer, wavelet transform modulus maxima method based on Marr wavelet is utilized for the ZrO2 ceramic coating with the thickness ranging from 250μm to 350μm.The results of ultrasonic method accords with that of metallographical results.
HU Xiao-fang, MA Jing, HU Da-wei, LIN Li-ying. Correlation of Powder’s Particle Size Distribution Fractal with Flowability and the Effect of Talc on Flowability[J]. Journal of Materials Engineering, 2007, 0(2): 42-45.
Powder’s particle size distribution fractal was used to denote particle size distribution and powder’s flowability,action of talc on the flowability of the powders which hold different fractal dimensions was discussed. The results show that powder’s particle size distribution fractal could denote the flowability of powder. After talc was adulterated into the powder, the flowability changed; when the adulteration ratio less than 2%(mass fraction),the smaller of the powder’s fractal dimension is, the more remarkable the flowability changes. When adulteration ratio reaches 3%~5%(mass fraction), the flowability of powders changes smoothly.
YE Xiao-ying, FENG Yan-qiu. ICP-AES Determination of Mn, Si, Al, Ti, Nb, La in Ultrahigh Strength Steel[J]. Journal of Materials Engineering, 2007, 0(2): 46-48.
An ICP-AES method for determining Mn,Si,Al,Ti,Nb,La in ultrahigh strength steel is presented. The spectral interference of matrix and coexist elements were studied and analytical lines were selected. Satisfactory linearity of working curve was obtained. The method was proved to be accurate and rapid through the accuracy and precision experiments.
HU Ben-fu, LIU Guo-quan, JIA Cheng-chang, TIAN Gao-feng. Development in New Type High-performance P/M Superalloys[J]. Journal of Materials Engineering, 2007, 0(2): 49-53,57.
P/M superalloys become first-choice material for turbine disks used for high thrust-weight ratio aeroengine due to the superior high excellent properties.The latest researches of the third generation new type high-performance P/M superalloys were analyzed and summarized, the preparation and mechanical properties of these alloys were reviewed with emphasis, and the development orientation was present to developing high-performance P/M superalloys.
ZHANG Jian, XU Guang-xing. The Seismic Behavior of Concrete Columns Confined with CFRP[J]. Journal of Materials Engineering, 2007, 0(2): 54-57.
On the basis of the confinement concrete system, the research on seismic behavior of the columns confined with carbon fiber reinforced plastics(CFRP) is paid much attention by researchers of many countries. The paper presented the state of art of CFRP confining concrete columns from the material character, structural experiments,the effect factors and the confinement mechanism and so on. Finally, some suggestions are presented according to the practical requirements.
MA Qing-song, CHEN Zhao-hui. Research and Development of Carbon Nanotubes Reinforced Ceramic Matrix Composites[J]. Journal of Materials Engineering, 2007, 0(2): 58-61,66.
Carbon nanotubes (CNTs) have many particular properties due to its particular structures. As a result, CNTs show application advantages not only in the fields of adsorption, hydrogen storage, catalyst support, cell electrode, sensor, semiconductor apparatus, and so on, but also in the fabrication of ceramic matrix composites with integral structural and functional properties. The research and development of CNTs reinforced ceramic matrix composites at home and abroad were reviewed, and the existing problems and the future research direction also were pointed out.
YUAN Bi-fei. Recent Progress in New Magnetic Field Controlled Shape Memory Alloys[J]. Journal of Materials Engineering, 2007, 0(2): 62-66.
The magnetic field controlled shape memory alloy is a new functional material with large magnetic field induced strain and high frequency,and it is one of the focus in the field of smart materials.The phase transformation and magnetic field induced strain characteristics of Ni-Mn-Ga alloys are summarized, and then the detailed progress in structure, phase transformation, shape memory effect and magnetic properties of Co-Ni-Ga and Ni-Fe-Ga alloys are introduced,problems in the research are discussed.
