材料期刊网

State-of-the-Art and Perspectives in the Field of Particulate Nanostructured Materials

R.A.Andrevski(Institute of New Chemical Problems , Russian Academy of Sciences , Chernogolovka , Moscow Region , 142432 Russia)

材料科学技术（英文）

A great attention has been paid to the research and development of nanostructured materials.The main preparation methods of ultrafine particles and nanostructured materials have been summarized. The applications of zone typical nanostructured materials have also been reviewed.The peculiar characteristics and properties. such as density, grain size, hardness, superplasticity,magnetic and catalytic properties have been discussed

关键词:

Key Problems in Microforming Processes of Microparts

Chunju WANG , Debin SHAN , Bin GUO , Jian ZHOU , Lining SUN

材料科学技术（英文）

From the viewpoint of production engineering, microforming is considered as an effective process to fabricate various microparts. Several key problems in microforming processes were investigated. A new microforming apparatus with a high stiffness piezoelectric actuator as the punch driver was developed to produce microparts. To improve the forming abilities and locate the billets, a floating microdie was designed. The size effects of the billets and die cavities on the microforming abilities were studied with upsetting and coining tests, respectively. And the isothermal microforming process of microgears was performed with the developed microforming apparatus. Several analysis methods were used to evaluate the forming quality of the microparts.

关键词: Microforming , 尺寸效应 , 微塑性成形设备 , 浮动

Key R&D activities for development of new types of wrought magnesium alloys in China

Transactions of Nonferrous Metals Society of China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs: the Key Technologies R&D Program of China, the National Basic Research Program of China, the National High-tech R&D Program of China, and the National Natural Science Foundation of China. The key R&D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.

关键词: wrought magnesium alloy;microstructure;properties;alloy designing;plastic deformation;research projects;y-zr alloys;mechanical-properties;mg-4y-4sm-0.5zr alloy;grain-refinement;rare-earth;microstructure;gd;phase;temperature;evolution

NEW INTERMETALLIC COMPOUNDS RCO(9)SI(4) (R=PR, ND) WITH A TETRAGONAL NAZN13-DERIVATIVE STRUCTURE

Journal of Alloys and Compounds

Two new intermetallic compounds RCo(3)Si(4) (R = Pr, Nd) with tetragonal NaZn13-derivative structure have been synthesized. Their crystal structures have been determined by X-ray powder diffraction and refined by the Rietveld technique. The space group for the tetragonal structure is 14/mcm. The lattice parameters are a = 7.789(1) Angstrom, c = 11.509(2) Angstrom and a = 7.791(2) Angstrom, c = 11.516(3) Angstrom for PrCo3Si4, and NdCo3,Si, respectively. The Si atoms strongly prefer to occupy the crystallographic 161(2) position.

关键词: crystal structure;intermetallic compounds;synthesis

STUDY ON THE PROBLEMS OF CONTACT IN THE NUMERICAL SIMULATION OF SHEET FORMING

K.F. Zhang , F.X. Diao , Q.F. Song , W. Wu , K.B. Chen and T.Xie Harbin Institute of Technology , Harbin 150001 , China

金属学报(英文版)

This study is concerned with the problems of contact in the process of numerical simulation of sheet metal forming in rigid visco-plastic shell FEM. In respect of analysis of sheet deep drawing process,for the tool model described by triangular elements, a kind of contact judging algorithm about the correlation between the node of deformed mesh and the triangular element of a tool is presented. In SPF/DB Lagrangian multiplier method is adopted to solve the contact problem between deformed meshes, and a new reliable practical dynamic contact checking algorithm is presented. As computation examples, the simulation results of metal sheet deep drawing and SPF/DB are introduced in this paper.

关键词: kcontact search algorithm , null , null , null

QUANTUM-CHEMICAL MODIFICATIONS OF SURFACE:NEW METHODS FOR PROTECTING MATERIALS FROM CORROSION

R. T. Malkhasyan

金属学报(英文版)

A new method of corrosion-resistant coating of technical iron is presented. Processingby vibrationally excited hydrogen molecules of the iron surface covered with oxide filmof a-Fe2O3 results in modification of surface by creating a film of amorphous ironon it. The presence of iron films with crystalline and amorphous phases, having thedifferent Fermi levels, leads tO formation of potential differences between them. Thispotential difference is opposite to the external electric field, resulting in decrease ofanode current and increase of corrosion resistance.

关键词: technical iron , null , null

High quality SiGe layer deposited by a new ultrahigh vacuum chemical vapor deposition system

Guangli LUO , Xiaofeng LIN , Peiyi CHEN , Peixin TSIAN

材料科学技术（英文）

An ultrahigh vacuum chemical vapor deposition (UHV/CVD) system is developed and the details of its construction and operation are reported. Using high purity SiH4 and GeH4 reactant gases, the Si0.82Ge0.18 layer is deposited at 550 degrees C. With the measurements by double crystal X-ray diffraction (DCXRD), transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) techniques, it is shown that the crystalline quality of the SiGe layer is good, and the underlying SiGe/Si heterointerface is sharply defined.

关键词:

FUNDAMENTAL PROBLEMS IN PULSED-BIAS ARC DEPOSITION

G.Q.Lin , Z.F.Ding , D.Qi

金属学报(英文版)

Arc deposition, a widely used surface coating technique, has disadvantages such aslarge droplet size and high deposition temperature. Recent trend in its renovation isthe introduction of pulsed bias at the substrate. The present paper attempts to describethe deposition process of TiN films using this technique with emphasis laid on theunderstanding of the basic problems such as discharge plasma properties, temperaturecalculation, and droplet size reduction. We show that this technique improves thefilm microstructure and quality, lowers deposition temperature, and allows coatingson insulating substrates. After analyzing load current oscillation behaviors, we havedetermined that the plasma load is of capacitance nature due to plasma sheath and thatit is equivalent to a circuit element consisting of parallel capacitance and resistance.At last, we point out the remaining problems and future development of the pulsed-biasarc deposition technique.

关键词: arc deposition , null , null

A NEW CONCEPT TOWARD INDUSTRIALIZATION OF Cu-Ⅲ-Ⅳ2 THIN FILM SOLAR CELLS AND SOME PRELIMINARY EXPERIMENT RESULTS

L.X.Shao

金属学报(英文版)

A new concept of full vacuum manufacturing for Cu-Ⅲ-Ⅳ2 thin-film solar cells has been discussed Cu-Ⅲ-Ⅳ2 thin-film solar cells manufactured using full in-line reactive sputtering will result in lower cost than that of the conventional method with CdS layer fabricated with chemical bath deposition (CBS) method. Using reactive sputtering process with organometallic gases, the compositions and electronic properties of Cu-Ⅲ-Ⅳ2 thin-film can be fine-tuned and precisely controlled, n-type Cu-Ⅲ-Ⅳ2 film and ZnS suffer layer can also be deposited using the in-line sputtering instead of using the CdS layer. The environmental pollution problems arising from using CdS can be eliminated and the ultimate goal of full in-line process development can then be realized. Some preliminary experimental results on a modal solar cell fabricated by the new technique in the new concept have been presented.

关键词: Cu-III-VI2 thin film solar cells , null

INTRODUCTION TO NEW TECHNOLOGY AND EQUIPMENTS IN PINGGUO ALUMINA REFINERY

S.J. Yang , G. Y. Gan and L.Z. Wang (Pingguo Aluminum Company , Guangxi 531400 , China)

金属学报(英文版)

The new technology and equipments used in alumina refinery in PINGGUO ALUMINUM COMPANY were introduced. Problems encountered during early period of its operation and improvements to the process and equipments were discussed. Current opemtion situation and pedect technical and economical figures were also introduced.

关键词: alumina , null , null , null