WR. Chen
,
J.Triantafillou
,
J. Beddoes and L. Zhao(Dept. of Mech. & Aero. Eng.
,
Carleton University
,
Ottawa
,
Canada Structures
,
Materials & Propulsion Laboratory
,
National Research Council
,
Ottawa
,
Canada Manuscript received 26 August 1996)
金属学报(英文版)
Creep of a polycrystalline near γ-TiAl alloy in two fully lamellar conditions is presented. A lamellar structure with fine interface spacing and planar grain boundaries provides improved creep resistance. The lamellar structure with wide interface spacing and interlocked grain boundaries has <1/2 the creep life, five times the minimum strain rate and greater tertiary strain.Creep strain is accommodated by dislocation motion in soft grains, but the strain rate is controlled by hard grains. The resistance to fracture is controlled by the grain boundary morphology, with planar boundaries causing intergranular fracture.To maximize the creep resistance of near γ-TiAl with a lamellar microstructure requires narrow lamellar interface spacing and interlocked lamellae along grain boundaries.
关键词:
:creep
,
null
,
null
,
null
,
null
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
Z. Yang
,
J.P. Li
,
J.X. Zhang
,
G.W.Lorimer
,
J. Robson
,
null
,
null
,
null
,
null
金属学报(英文版)
The current research and development of magnesium alloys is summarized. Several aspects of magnesium alloys are described: cast Mg alloy, wrought Mg alloy, and novel processing. The subjects are discussed individually and recommendations for further study are listed in the final section.
关键词:
Magnesium alloys
,
null
,
null
Zheng FANG
,
Quanru ZHANG
,
Hengzhong ZHANG
,
Yuan FANG
材料科学技术（英文）
The thermoelectrochemistry (TEC), a novel cross discipline, is presented, including the basic equations for a cell and a half-cell reaction, the treatment of experimental data and its application to electro-generative leaching of mineral and to measuring thermodynamic and kinetic data of an electrode reaction. The TEC technology will play an important part in the research on the metallurgical process under various fields.
关键词:
新型炭材料
The uptake of hydrogen in carbon nanotubes is a hot topic in carbon nanotube research. Currently there are two methods to store hydrogen in carbon nanotubes. One is based on gas phase hydrogen storage and the other is based on an electrochemical method. Fundamental principles, theoretical calculations, and the interaction between hydrogen and carbon nanotubes for electrochemical hydrogen storage are reviewed. In particular, an overview of the most recent progress on electrochemical hydrogen storage in both single-walled carbon nanotubes and multi-walled carbon nanotubes is given and the prospect of their use in high performance batteries is highlighted.
关键词:
carbon nanotubes;electrochemistry;gas storage;nanofibers;adsorption
Huiguan WAN
,
Xiumei QI
,
Jing TIAN
,
Yuyong CHEN
,
Weiqiang ZHA
,
Jun JIA
材料科学技术（英文）
In this research, the materials and the compositions of the surface slurries were chosen by considering the characteristics of Ti investment casting. The effects of solid-liquid ratios on the properties of the slurry and the effects of baking temperatures on the flexural strength have also been investigated. Flawless shells having smooth inner surface were manufactured with proper technology. Ti and its alloys were melted and poured by water-cooled Cu crucible vacuum induction furnace. The qualities of the investment castings made accordingly were studied and analyzed.
关键词:
D. N. He
,
X. F. Yin
,
H. Z. Thao
,
D. L*
,
X. Y. Ruan
,
J. L. Cheng and J. Y. Jiang 1) Shanghai Jiao Tong University
,
National Die & Mold CAD E. R. C
,
Shanghai 200030
,
China 2) Shanghai Vopkswagen Automotive Company Ltd.
,
Shanghai 201805
,
China Manuscript received
金属学报(英文版)
The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other plastic process. The common test methods in laboratories are analyzed. It shows that though all those test methods can test the friction coefficient, the probe test method is most suitable for the research of friction and lubrication and the process in deep drawing, for this method is identical with the actual work condition either from the test principle or deformation status of the blank. Last the successful application in the deep drawing simulator newly developed the the probe method are intro- duced in detail.
关键词:
deep drawing
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null
,
null
,
null
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
