材料期刊网

APPLICATION OF CtPARAMETER FOR CREEPFATIGUE CRACKGROWTH WITH SLOW LOAD RISING CONDITION

Author J.H. Lee 1) , K.B. Yoon2) , Y.J. Kim3)and U.B. Baek4) 1) Engineering Research Department , Korea Institute of Nuclear Safety , P.O. Box 114 , Yoosung , Taejon 305600 , Korea2) Department of Mechanical Engineering , Chung Ang University , 221 Huksuk , Dongjak , Seoul 156756 , Korea3) Department of Mechanical Engineering , Sungkyunkwan University , 300 Chunchun , Jangan , Suwon 440746 , Korea4) Failure Prevention Research Center , Korea Research Institute of Standards and Science , P.O. Box 102 , Yoosung , Taejon 305600 , KoreaManuscript received 18 October 1998

金属学报(英文版)

Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However, crack growth due to creep can also occur under load varying conditions when load rising time is so long that accumulated creep deformation near the crack tip is not negligible.In this paper, the estimation equation of the Ctparameter which can be applied to the case of slow load rising, i.e., (Ct)r, is explained. And the correlation between (Ct)r at the end of the load increasing period and Ct at the beginning of the succeeding load hold period is discussed. Finite element analyses of several cases with various loading conditions were performed and results were presented to show the effectiveness of the proposed Ct estimation scheme. The general applicability of the equation is also discussed.

关键词: creep , null , null , null , null , null

R & D ACTIVITIES ON AEROSPACE MATERIALS IN KOREA

H.M. Kim(Korea Institute of Machinery and Materials , Korea Manuscript received 26 August 1996)

金属学报(英文版)

This paper briefly reviews research and development programs in Korean aerospace industry,with an emphasis on aircraft materials technology. International collaborations in these areas are outlined and the R & D activities are highlighted against the　background of the national economy.It is shown that the investment from government agencies and large enterprises has led to healthy development of aerospace materials industries in Korea.

关键词: :R & D , null , null , null

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（英文）

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Laser-Heated Diamond-Anvil Cell (LHDAC) in Materials Science Research

N.V.Ch , ra Shekar , P.Ch.Sahu , K.Govinda Rajan

材料科学技术（英文）

Laser-heated diamond-anvil cell (LHDAC) is emerging as the most suitable, economical and versatile tool for the measurement of a large spectrum of physical properties of materials under extreme pressure and temperature conditions. In this review, the recent developments in the instrumentation, pressure and temperature measurement techniques, results of experimental investigations from the literature were discussed. Also, the future scope of the technique in various avenues of science was explored.

关键词: Laser heating , null , null , null

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）

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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）

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THE CHANGING ROLE OF THE NATIONAL LABORATORIES IN MATERIALS RESEARCH

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

Stereology in Materials Science

LIU Guoquan Department of Materials Science and Engineering , University of Science and Technology Beijing , 100083 , China.

材料科学技术（英文）

Quantitative analysis of populations having a geometric structure,which has developed into a special scientific subject called microstructology or stereology,is of great importance to the characterization and evaluation of microstructures and their evolution in various processes.This paper, besides a brief discussion on those topics such as the recent developments of computer assisted image analysis,mathematical morphology,and fractal analysis,will mainly focus on the scope,fundamen- tals,present status,and perspectives of classical stereology.Several case examples of its application to materials science will also be given.

关键词: stereology , 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

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