材料期刊网

PHASE CONSTITUTE AND MICROGRAPHY OF REACTION SYNTHESIS OF Al+Ti+C SYSTEM

ZHANG Erlin , ZENG Songyan , ZENG Xiaochun , LI Qingchun(Harbin institute of Technology , Harbin , ChinaManuscript received 7 April 1995)

金属学报(英文版)

In this paper,the effects of aluminum content,C/Ti ratio and the size of powders on the phase constitute and micrography of reaction synthesis of Al+Ti+C system have been studied by the use of XRD and SEM.It has been shown that with the increase of aluminum content,in addition to TiC,Al_3Ti phase is also synthesised,and the content of Al_3Ti increase,and the size of TiC become fine,changing from 0.4-1.4μm.The increase of C/Ti ratio is favorable to the synthesis of TiC and can increase the Al content in which only TiC phase has formed,and has no effect on the micrography of TiC,but shows great in fluence on the micrography,of Al_3Ti.In addition,the size of titanium has no effect on the phase constitue and micrography,but the size of aluminum has great in fluence on them.With the increase of size of aluminum powder,Al_3Ti will be synthesised and its content increase also,so it is unfavorable to the synthesis of TiC.

关键词: :composite , null , null , null

Brief Outline of the Metallurgy Department of Kunming Institute of Technology

LIU Chunpeng Kunming Institute of Technology , Kunming 650093 , China.

材料科学技术（英文）

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Microstructures and Dielectric Properties of Ba_1-xSr_xTiO₃ Ceramics Doped with B₂O₃-Li₂O Glasses for LTCC Technology Applications

Xiujian Chou

材料科学技术（英文）

Ba_1-xSr_xTiO₃ ceramics, doped with B₂O₃-Li₂O glasses have been fabricated via a traditional ceramic process at a low sintering temperature of 900 °C using liquid-phase sintering aids. The microstructures and dielectric properties of B₂O₃-Li₂O glasses doped Ba_1-xSr_xTiO₃ ceramics have been investigated systematically. The temperature dependence dielectric constant and loss reveals that B2O3-Li₂O glasses doped Ba_1-xSr_xTiO₃ ceramics have diffusion phase transformation characteristics. For 5 wt% B₂O₃-Li₂O glasses doped Ba0:55Sr0:45TiO₃ composites, the tunability is 15.4% under a dcpplied electric field of 30 kV/cm at 10 kHz; the dielectric loss can be controlled about 0.0025; and the Q value is 286. These composite ceramics sintered at low temperature with suitable dielectric constant, low dielectric loss, relatively high tunability and high Q value are promising candidates for multilayer low-temperature co-fired ceramics (LTCC) and potential microwave tunable devices applications.

关键词: Sintering

Titanium technology in the USA - an overview

D.Eylon , S.R.Seagle

材料科学技术（英文）

The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.

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NUMERICAL ANALYSIS OF THREE-DIMENSIONAL FLUID FLOW AND HEAT TRANSFER IN TIG WELD POOL WITH FULL PENETRATION

WU Chuansong , CAO Zhenning , WU Lin Harbin Institute of Technology , Harbin , China

金属学报(英文版)

A model is established to analyze three-dimensional fluid flow and heat transfer in TICweld pools with full penetration.It considers the deformation of the molten pool surfaceat the condition of full penetrated workpieees,takes the are pressure as the drivingforce of the pool surface deformation,and determines the surface configuration of weldpool based on the dynamic balance of arc pressure,pool gravity and surface tension atdeformed weld pool surface. The SIMPLER algorithm is used to calculate the fluid flowfield and temperature distribution in TIG weld pools of stainless steel workpieces.TIGwelding experiments are made to verify the validity of the model.It shows the calculatedresults by the model are in good agreement with experimental measurements. professor,Dept of Welding Engineering,Harbin Institute of Technology,Harbin 150006,China

关键词: KEY WORDS TIG weld pool , null , null , null , null

Development and application of universal formability technology

Yanwu Xu

材料科学技术（英文）

Using mathematical plasticity theories, universal formability (UF) technology has been developed and applied in the automotive stamping engineering and production. As a formability analysis tool, this technology is the major methodology for the development of stamping expert system (solution provider) for (a) product design and feasibility analysis, (b) material automatic selection using nomograms, (c) draw die design using pre-models, and (d) UF and robustness analysis of die performance in finite element analysis (FEA) environment.

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Residual Stresses in Coating Technology

G.Montay , A.Cherouat , A.Nussair , J.Lu

材料科学技术（英文）

Residual stress in coatings is the result of individual particle stress. Their effects may be either beneficial or detrimental, depending upon the magnitude, sign and distribution of the stresses with respect to the external load. Tensile stress which exceeds the elastic limit causes cracking in surface coatings or at the interface between the substrate and the coat. Compressive stress, in general, has a beneficial effect on the fatigue life, crack propagation, coating adhesion and on the durability of the top coat during service. Compressive residual stresses can increase the number of cycles before crack initiation begins through a mean stress effect. Temperature gradients which occur during solidification and subsequent cooling are the principal mode of internal stresses generation. Some parameters influence the residual stress field of both the coating and the substrate. Substrate nature, spraying temperature, thickness of the coat layer, substrate preparation (grit blasting conditions), and velocity of the splats are in the relation with the quality of the coating. In this work, we will describe the role playing by the ceramics coating elaboration on the residual stress gradient in depth of the component. The incremental hole drilling technique has been developed to determine the residual stress gradient in depth of the coat and substrate which must be used with particularly conditions. This new technology has been employed on zirconia, alumina and tungsten carbide plasma sprayed coating.

关键词: Coating , null , null , null

Recent Advances of Laser Coating Technology in China

LIANG Yong LI Ruiguo Institute of Metal Research , Academia Sinica , Shenyang 110015 , ChinaInstitute of Corrosion and Protection of Metals , Aademia Sinica , Shenyang , 110015 , China

材料科学技术（英文）

Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.

关键词: laser , null , null , null , null

Kunming Institute of Precious Metals

WANG Yonglu NING Yuantao Kunming Institute of Precious Metals , Kunming , China.

材料科学技术（英文）

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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