材料期刊网

Fatigue Crack Growth of Al-Li Alloy 2091 in 3.5% NaCl Solution and at 130℃

HE Shiyu WANG Zhongguang LI Qingjian ZHANG Yun FENG Xiaozeng State Key Laboratory for Fatigue and Fracture of Materials , Institute of Metal Research , Academia Sinica , Shenyang , 110015 , ChinaDept.of Materials Science and Engineering , Harbin Institute of Technolo

材料科学技术（英）

A study has been made of the fatigue crack growth in an Al-Li alloy 2091 in 3.5%NaCl solu- tion and at an elevated temperature of 130℃.The aging and environmental effects on the crack growth behaviour were examined.It is shown that the fatigue crack growth resistance decreases with aging.The specimen with underaged structures shows the highest resistance to fatigue crack growth due to more deflected crack paths and the resulting high crack closure levels.As compared to laborato- ry air,both 3.5% NaCl solution and elevated tem- perature of 130℃ cause an increase of near-thresh- old crack growth rates and a decrease of threshold levels.The elevated temperature is more effective. The effect of elevated temperature is mainly due to the precipitate coarsening which results in an enhancement of slip irreversibility.Hydrogen embritttlement is supposed to be responsible for the degradation of fatigue crack growth resistance in 3.5%NaCl solution

关键词: fatigue crack growth , 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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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）

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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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Institute of Materials Science at Jilin University——A Brief Overview

WANG Yuming Institute of Materials Science , Jilin University , Changchun , 130023 , China

材料科学技术（英）

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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

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

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）

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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

High strength and high electrical conductivity in bulk nanograined Cu embedded with nanoscale twins

Applied Physics Letters

A bulk nanograined Cu sample embedded with nanoscale twins is produced by means of dynamic plastic deformation at cryogenic temperatures. It exhibits a tensile yield strength of 610 MPa and an electrical conductivity of 95% IACS at room temperature. The unique combination of a high strength and a high conductivity is primarily attributed to the presence of a considerable amount of nanoscale twins which strengthen the material significantly while having a negligible influence on electrical conductivity. (C) 2007 American Institute of Physics.

关键词: nanocrystalline cu;tensile properties;grain-boundaries;metals;dislocations;resistivity;copper