材料期刊网

SOLIDIFIED PRODUCT FROM Bi-Sr-Ca-Cu-O MELT AND ITS TRANSFORMATION INTO SUPERCONDUCTOR

ZHANG Cheng HU Zhuangqi GE Yunlong WANG Yongzhong QIAO Guiwen Institute of Metal Research , Academia Sinica , Shenyang , China doctorate student Institute of Metal Research , Academia Sinica , Shenyang 110015 , China

金属学报(英文版)

The Bi_2(Sr,Ca)_3Cu_2O_x system superconductor was prepared by different melting procedures and after treatment.The effects of cooling rate,annealing temperature and time,as well as melting procedures on phase transformation were investigated.The structure and properties were examined by X-ray diffraction,optical microscopy,EPMA,DTA,TGA and measurements of electric and magnetic properties.When the melt of nominal composition Bi_2(Sr,Ca)_3Cu_2O_x solidified in air,the Bi_2(Sr,Ca)_3Cu_2O_(8+δ)(2212)superconducting phase is stable,the easily solidified product including Bi_2(Sr,Ca)_2CuO_(6+δ)(2201)phase is metastable, and another may be amorphous if rapidly quenched.The last two may transform into 2212 phase by after treatment at an optimal annealing temperature ranging 780—870℃.While 2201 phase,prepared by the laser floating zone melting method,may easily transform into 2212 phase at layer or filament in shape which is favourable to improve the links among superconducting grains and critical current density.

关键词: Bi system superconductor , null , null , null

Introduction to atmospheric corrosion research in China

Science and Technology of Advanced Materials

In this paper, we introduce the research on atmospheric corrosion in China. We describe the climate characteristics and the classification of atmospheric corrosivity across the whole country. We also describe the rusting evolution under simulated wet/dry cyclic conditions. (C) 2007 NIMS and Elsevier Ltd. All rights reserved.

关键词: atmospheric corrosion;corrosivity;rusting evolution;weathering steels;rust;mechanism;so2;o-3;no2

MICROSTRUCTURE AND PROPERTIES OF SiC_w/6061Al COMPOSITE The Author is now with Institute of Metal Research,Academia Sinica,China

MA Zongyi YAO Zhongkai Harbin Institute of Technology , Harbin , China

金属学报(英文版)

The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure

关键词: composite , null , null , null

Recent developments in high temperature intermetallics research in China

Intermetallics

A comprehensive survey was made of various advances of intermetallics research in China. The investigation focussed on the fundamental research and materials development. Charge density distribution and site occupancy of alloying elements, environmental embrittlement and chemical reaction, interface structures and phase transformation at the atomic scale, nanocrystalline intermetallics and its thermal stability, superplastic behavior and anomalous yield strength peak are reviewed. Several Ti-Al and Ni-Al based alloys have been manufactured, and show good mechanical properties. Diverse components have been fabricated successfully. (C) 2000 Elsevier Science Ltd. All rights reserved.

关键词: aluminides, miscellaneous;hydrogen embrittlement;mechanical properties;at high temperatures;superplastic behavior;phase interfaces;grain-boundary fracture;in-situ composites;environmental;embrittlement;hydrogen embrittlement;ni3al;compression;alloys;co3ti;boron;feal

Luoyang Institute of Refractories Research Ministry of Metallurgical Industry

ZHONG Xiangchong Luoyang Institute of Refractories Research , Luoyang , China.

材料科学技术（英文）

关键词:

Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

Development of Cast Superalloys for Gas Turbines in China

CHEN Rongzhang CHEN Wanhua Institute of Aeronautic Materials , Beijing 100095 , China.

材料科学技术（英文）

As in other countries,significant achievements in the research of cast superalloys for many years have also been obtained in China.These results are important contribu- tion to the development of aero and land-based gas tur- bine engines.

关键词: cast superalloy , null

Discovery and Research of High Tc Superconductor in the Institute of Physics, Academia Sinica

CHEN Liquan A special member of CCAST (World Laboratory) , Post Address: Institute of Physics , Academia Sinica , P.O. Box. 603. Beijing , China.

材料科学技术（英文）

关键词:

Technical note: Research and development of localized corrosion rate monitoring instrument for nonpassivable metal in corrosive media

Corrosion

This paper introduces the design of a localized corrosion rate monitoring instrument that can monitor and evaluate the maximum and stable localized corrosion rate of a nonpassivable metal in a corrosive environment by measuring the current density in a corrosion sensor with an occluded anode.

关键词: instrument;localized corrosion rate;monitor

Key R&D activities for development of new types of wrought magnesium alloys in China

Transactions of Nonferrous Metals Society of China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs: the Key Technologies R&D Program of China, the National Basic Research Program of China, the National High-tech R&D Program of China, and the National Natural Science Foundation of China. The key R&D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.

关键词: wrought magnesium alloy;microstructure;properties;alloy designing;plastic deformation;research projects;y-zr alloys;mechanical-properties;mg-4y-4sm-0.5zr alloy;grain-refinement;rare-earth;microstructure;gd;phase;temperature;evolution