ZHO U Bangxin Southwest Centre for Reactor Engineering Research and Design
,
Chengdu
,
China Bangxin
,
Professor
,
P.O.Box 291-106
,
Chengdu 610005
,
China
金属学报(英文版)
After70-90% cold-rolling,strong{111}〈110〉and weak {111},〈112〉 cold-rolled tex- tures and perfect{111}〈112〉 recrystallization texture were obtained in Fe-Si single crys- tals.The cold-rolled textures with different orientations possesses different ability for recov- ery because of the difference of dislocation structure and store energy alter cold-rolling.The recovery taking place at{111}〈112〉orientation region was prior to that at{111}〈110〉 orientation region.hese subgrains with{111}〈112〉 orientation became recrvstallization nuclei during their growth at expending the surrounding matrix which was sluggish in recovery process.The development of recrystallization textures may be suggested as a process of “nucleation in-situ-selective growth”.The formation of(111)textures in low carbon steel sheets has been discussed in the light of this suggestion.
关键词:
Fe-Si single crystal
,
null
,
null
,
null
Yaping ZONG
,
Liang ZUO
材料科学技术（英文）
A concept of microstructure design for materials or materials microstructure engineering is proposed. The argument was suggested based on literature review and some our new research work on second phase strengthening mechanisms and mechanical property modeling of a particulate reinforced metal matrix composite. Due to development of computer technology, it is possible now for us to establish the relationship between microstructures and properties systematically and quantitatively by analytical and numerical modeling in the research scope of computerization materials. Discussions and examples on intellectual optimization of microstructure are presented on two aspects: grain boundary engineering and optimal geometry of particulate reinforcements in two-phase materials.
关键词:
Microstructure design
,
null
,
null
Andrej Atrens
材料科学技术（英文）
Corrosion research by Atrens and co-workers has made significant contributions to the understanding of the service performance of engineering materials. This includes: (1) elucidated corrosion mechanisms of Mg alloys, stainless steels and Cu alloys, (2) developed an improved understanding of passivity in stainless steels and binary alloys such as Fe-Cr, Ni-Cr, Co-Cr, Fe-Ti, and Fe-Si, (3) developed an improved understanding of the melt spinning of Cu alloys, and (4) elucidated mechanisms of environment assisted fracture (EAF) of steels and Zr alloys. This paper summarises contributions in the following: (1) intergranular stress corrosion cracking of pipeline steels, (2) atmospheric corrosion and patination of Cu, (3) corrosion of Mg alloys, and (4) transgranular stress corrosion cracking of rock bolts.
关键词:
Stress corrosion cracking
,
null
,
null
Qingfen LI
,
Zhaoxia CUI
,
Weimin WANG
,
Jianhua GAO
材料科学技术（英文）
An expert system prototype for fibre-reinforced plastic matrix (FRP) composite material design, ESFRP, has been developed. The system consists of seven main functional parts: a general inference engine, a set of knowledge bases, a material properties algorithm base, an explanation engine, various data bases, several function models and the user interface. The ESFRP can simulate human experts to make design scheme for fibre-reinforced plastics design, FRP layered plates design and FRP typical engineering components design. It can also predict the material properties and make strength analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.
关键词:
J. Brnic
,
G. Turkalj and M. Canadija Faculty of Engineering
,
Vukovarska 58
,
51000 Rijeka
,
Croatia
金属学报(英文版)
The optimization problems belong to the family of the most important engineering problems. The objective of this paper is to proposed a very efficient numerical algo- rithm which is involved in an optimal design procedure in the field of viscoplasticity phenomena. Because of the complexity of design procedure, particularly in the field of viscoplas- ticity, the finite element method is used. This method provides a good structural discretization and very efficient mathematical describing of time-rate effects. Accord- ing to the design specifications, which will dictate a limiting design strain, using the proposed algorithm, the design life of the considered structure will be covered. For the justification of the proposed method an example is presented. On the basis of specifications data and environment conditions, an operating pressure of a pressure vessel is obtained.
关键词:
optimal design
,
null
,
null
,
null
Materials Science & Engineering C-Biomimetic Materials Sensors and Systems
Bamboo, one of the strongest natural structural composite materials, has many distinguishing features. It has been found that its reinforcement unit, hollow, multilayered and spirally-wound bast fiber, plays an extremely important role in its mechanical behavior. In the present work, on the basis of the study on bamboo bast fiber and wood tracheid, a biomimetic model of the reinforcing element, composed of two layers of helically wound fiber, was suggested. To detect the structural characteristics of such a microstructure, four types of macro fiber specimens made of engineering composites were employed: axially aligned solid and hollow cylinders, and single- and double-helical hollow cylinders. These specimens were subjected to several possible loadings, and the experimental results reveal that only the double-helical structural unit possesses the optimum comprehensive mechanical properties. An interlaminar transition zone model imitating bamboo bast fiber was proposed and was verified by engineering composite materials. In our work, the transition zone can increase the interlaminar shear strength of the composite materials by about 15%. These biomimetic structural models can be applied in the design and manufacture of engineering composite materials.
关键词:
bamboo;bast fiber;biomimetics;engineering composites
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
Modelling and Simulation in Materials Science and Engineering
In order to study the growth of diamond films over a large area in a traditional hot-filament chemical vapour deposition (HFCVD) reactor, two-dimensional mathematical models were first developed to investigate the temperature fields of the reactor walls, which made significant contributions to thermal round-flow of the reactant gases under different energy transfer systems. The set of partial differential equations involved in the thermal conduction system was solved with different boundary conditions by the finite control volume method. Numerical simulations showed that the temperature space distributions were heterogeneous when thermal radiation was assumed to be the only mechanism in heat transfer from the filaments to the reactor walls. However, taking into account the effects of thermal conduction under adiabatic and different isothermal temperature boundary conditions, the temperature uniformities improved greatly. In addition, thermal convection did not affect the temperature distributions but only increased the total temperature of the reactor wall. These results not only give insight into the dominant reasons resulting in low nucleation density and low growth rate of diamond films, but also provide a basis for the design of industrial HFCVD reactors to obtain high-quality diamond films over a large area.
关键词:
chemical-vapor-deposition;heat-transfer;gas-flow;hfcvd
