材料期刊网

Quasicrystalline Phase in As-cast Mg-Zn-Y-Zr Alloy

Yali TANG , Ningfu SHEN and Xin YUAN (Research Center for Materials , Zhengzhou Institute of Technology , Zhengzhou , 450002 , China)Zhiping LUO and Shaoqing ZHANG (Institute of Aeronautical Materials , Beijing , 100095 , China)(To whom correspondence should be ad

材料科学技术（英）

An icosahedral phase in as-cast Mg 5. 78Zn-0.89Y-0.48Zr (wt-%) alloy has been identified with transmission electron microscope (TPM) The selected area diffraction patterns (SADP) from the phase show a five-fold symmetry of a quasicrystalline structure. The energy dispersive X-ray spectra (EDXS) indicate that the quaternary phase has a chemical composition of 67.6Zn-1 9.4Mg-8,1 Y-4 9Zr in at -%

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A DEVELOPMENT STUDY OF CAST COPPER ALLOY WITH HIGH STRENGTH AND HEAT-RESISTANCE

WANG Zheng , REN Chenxing and WANG Suying(Department of Materials Science , Zhengzhou Institute of Technology , Zhengzhou 450002 , China)Manuscript received 2 January 1996 , in revised form 7 March 1996)

金属学报(英文版)

By means of Precipitation hardening, a cast copper alloy with high strength and heatresistance named Cu-6Ti-Cr-Al has been developed. This alloy has good castability. After water quenching at 860℃ for 1 h and aging at 450℃ for 4 h, the tensile strength, σ_b, is greater than 890MPa and the compressive strength, σ_(bc), reaches 1300MPa, while the ratio of compression, ε_c, is maintained at 20%. When the environmental temperature is raised to 450℃, the mechanical properties do not show any appreciable loss. These copper alloy castings have been used on the roll sleeves of rubber formers and the journal bearings of sheet mills. The results have shown that the service life of these parts is much longer than that of aluminium bronze and 904alloy castings. In the present work, the microstructure, mechanical properties and strengthening mechanism were investigated.

关键词: : cast copper alloy , null , null , null

ACTIVATION MECHANISM OF AMORPHOUS Ni_(63)Zr_(32)La_5 ALLOY HYDROGENATION CATALYST

X.K. Wang. N. F. Shen and G.J Lei(Dept. of Materials Science and Engineering , Zhengzhou Institute of Technology , Zhengzhou 450002 , China)H. C. Gu(Dept. of Materials Science and Engineering. Xi'an Jiaotong University , Xi'an 710049 , China Manuscript received 27 September 1995)

金属学报(英文版)

The catalytic activity of amorphous Ni_63 Zr_32 La_5 ribbon for hydrogenation of ethyne to ethylene can be greatly enhanced when the alloy ribbon is pretreated with dilute acid solution,heated under negative atmosphere pressure and subjected to hydrogen reduction successively. The change of surface state of the ribbon during the activation has been analysed by AES and XPS. The surface of as-received ribbon is covered with a thin film of La_2 O_3. After pretreatment. the surface concentrations of both Ni and Zr increase obviously, whereas the surface concentration of La decreases markedly.Finally, on the surface of activated catalyst the Ni and NiO disperse finely on the matrix consisting of oxides of both Zr and La and a small amount of fluorides of Zr and La.

关键词: :amorphous Ni_(63) Zr_(32) La_5 alloy;catalyst;activation mechanism

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）

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Titanium technology in the USA - an overview

D.Eylon , S.R.Seagle

材料科学技术（英）

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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Development and application of universal formability technology

Yanwu Xu

材料科学技术（英）

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）

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）

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）

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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