材料期刊网

A Near-bulk Quasicrystal Alloy Formed in Zn-Mg-Y System

Yali TANG , Ningfu SHEN , Xiaofang LIU(Research Center for Materials , ZhengZhou University of Technology , Zhengzhou 450002 , China)Zhiping LUO(Institute of Aeronautical Materials , Beijng 100095 , China)Baicheng LIU(Tsinghua University , Beijing 100084 , China)

材料科学技术（英文）

Zn-Mg-Y and Mg-Zn-Y-Zr ingots with different chemical compositions were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The icosahedral phases were found in all alloys studied in present work under the as-cast conditions. There are nearly all quasicrystal phases with some MgZn2 Laves phase in a Zn-28.31Mg-13.80Y alloy (wt pct).After annealing at 400℃ for 8 h, the quasicrystal phases transformed to an fcc "W" phase in an Mg-5.57Zn-1.08Y-0.60Zr alloy (wt pct).

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THE CHANGING ROLE OF THE NATIONAL LABORATORIES IN MATERIALS RESEARCH

WADSWORTH Jeffrey and FLUSS Michael(Chemistry and Materials Science Directorate , Lawrence Livermore National Laboratory , Livermore , CA 94551)

金属学报(英文版)

The role of the National Laboratories is summarized from the era of post World War II to the present time. The U.S. federal government policy for the National Laboratories and its influence on their materials science infrastructure is reviewed with respect to .determining overall research strategies, various initiatives to interact with industry (especially in recent years),building facilities that serve the nation, and developing leading edge research in the materials sciences. Despite reductions in support for research in the U.S. in recent years, and uncertainties regarding the specific policies for Research &Development (R&D) in the U.S., there are strong roles for materials research at the National Laboratories. These roles will be centered on the abilities of the National Laboratories to field multidisciplinary teams, the use of unique cutting edge facilities, a focus on areas of strength within each of the labs,increased teaming and partnerships, and the selection of motivated research areas. It is hoped that such teaming opportunities will include new alliances with China, in a manner similar, perhaps, to those recently achieved between the U.S. and other countries.

关键词: : U.S. Materials Science. U.S. National Laboratories and Facilities , null

RESEARCH AND DEVELOPMENT OF HIGH TEMPERATURE STRUCTURAL MATERIALS FOR AERO-ENGINE APPLICATIONS

G.Q. Zhang

金属学报(英文版)

The status of research, development of superalloys and materials processing & fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superalloys for aero-engine disks and rings, and powder metallurgy (PM) superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.

关键词: superalloy , null , null

Research and development of carbon materials for electrochemical capacitors - II - The carbon electrode

新型炭材料

The state-of-the-art research and development of various carbons for possible application as the electrode material in electrochemical capacitors (ECs) are summarized. The main factors affecting the properties of ECs are carefully reviewed, from the material characteristics such as specific surface area, pore size distribution and pore volume, surface functional groups and graphitic orientation of the carbon materials, to the electrode characteristics and electrochemical aspects such as electrode preparation process, electrode density and thickness, electrode conductivity and pseudo-capacitance, etc. In particular, an overview is given of the most recent progress in electrochemical capacitors using carbon nanotubes as the electrode material and the prospect of their use in this application is highlighted.

关键词: electrochemical capacitors;carbon electrode;carbon nanotubes;double-layer capacitors;activated carbon;nanotube electrodes;supercapacitor electrodes;organic electrolyte;deposition;fiber

Research and development of carbon materials for electrochemical capacitors I. Electrochemical capacitors

新型炭材料

Electrochemical capacitors (ECs) store energy in eletric double-layers formed along the interface of electrode material and electrolyte, this produces an extremely large capacitance compared with the traditional capacitors. The fundamental principles of electrochemical capacitors are briefly introduced, and the key materials used like electrode materials, electrolytes, separator and current collector materials are summarized. Electrochemical capacitors with pseudocapacitance, such as metal oxides, polymers and hybrid capacitors, are also discussed. The characteristics, possible application fields, the development state, the future R&D prospects for electrochemical capacitors are highlighted.

关键词: electrochemical capacitors;supercapacitors;storage of electric energy;principles

RESEARCH ON MEASURING METHOD OF THE THERMAL CONDUCTIVITY FOR HIGHLY POROUS MATERIALS

J Y Wu , Z.M. Tang , W Shi andR.Z. Wang (Institute of Refrigeration and Cryogenics Engineering , Shanghai Jiao Tong University , Shanghai 200030 , China)

金属学报(英文版)

A transient method with rectangular pulse heating has been developed to measure the thermal conductivity of highly porous materials such as activated carbon, zeolite and silica gel. By this method the thermal conductivity can be measured quickly and accu-rately. In this paper, a set of automatically controlled testing equiptnent is presented.The measuring method is analysed. The thermal conductivities of some samples, such as activated carbon and zeolite, are measured by the equipment. A group of useful data has been obtained.

关键词: thermal conductivity , null , null

Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science Research

N.V.Ch , ra Shekar , P.Ch.Sahu , K.Govinda Rajan

材料科学技术（英文）

Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.

关键词: Laser heating , null , null , null

Research on microcapsules of phase change materials

稀有金属（英文版）

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Advanced Materials for Energy Storage

Advanced Materials

Popularization of portable electronics and electric vehicles worldwide stimulates the development of energy storage devices, such as batteries and supercapacitors, toward higher power density and energy density, which significantly depends upon the advancement of new materials used in these devices. Moreover, energy storage materials play a key role in efficient, clean, and versatile use of energy, and are crucial for the exploitation of renewable energy. Therefore, energy storage materials cover a wide range of materials and have been receiving intensive attention from research and development to industrialization. In this Review, firstly a general introduction is given to several typical energy storage systems, including thermal, mechanical, electromagnetic, hydrogen, and electrochemical energy storage. Then the current status of high-performance hydrogen storage materials for on-board applications and electrochemical energy storage materials for lithium-ion batteries and supercapacitors is introduced in detail. The strategies for developing these advanced energy storage materials, including nanostructuring nano-/microcombination, hybridization, pore-structure control, configuration design, surface modification, and composition optimization, are discussed. Finally, the future trends and prospects in the development of advanced energy storage materials are highlighted.

关键词: lithium-ion batteries;carbon nanotube electrodes;enhanced hydrogen;storage;metal-organic frameworks;double-layer capacitors;n-h system;carbide-derived carbons;ammonia borane dehydrogenation;ordered;mesoporous carbons;high-rate performance

R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null