材料期刊网

EFFECT OF NITROGEN ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ALLOY HK50

YU Yongsi CAO Zhiben WANG Fugang , Dalian University of Technology , Dalian , ChinaGUO Xiaobing Jinzhou Institute of Technology , Jinzhou , China Associate Professor , Dept.of Materials Science , Dalian University of Technology , Dalian 116024 , China

金属学报(英文版)

The volume fraction of the lamellar carbide cell in HK50 alloy may be increased with the in- crease of nitrogen content over 0.065%.The habit plane of l(?)mellar carbide is {111}_γ.The distribution of nitrogen changes no more before or after the precipitation of lamellar structure. The diffusion activation energy of carbon reduces remarkably with the increase of nitrogen content.It is believed that the lamellar carbide cell is harmful to the high temperature creep and impact properties of the alloy.

关键词: alloy HK50 , null , null , null

SLIP FEATURE AND GRAIN BOUNDARY BEHAVIOURS OF Ni_3Al ALLOYS DURING DEFORMATION

LIN Dongliang , (T.L.Lin) , CHEN Da Shanghai Jiaotong University , Shanghai , China Professor , Dept.of Materials Science , Shanghai Jiaotong University , Shanghai 200030 , China

金属学报(英文版)

The deformation behaviours of Ni_3Al alloys with various chemical compositions and subjected to different heat treatments were in situ observed under SEM. Moreover,in situ observations of slip trace were supplemented by the direct observation of dislocation arrangements under TEM.In B-doped Ni_3Al alloys it is shown that close to the grain boundary there exists a thin slip transition region,within which slip lines are reoriented or other slip systems are operated to produce a local strain accommodation and to relax the stress concentration at grain bound- aries.Boron seems to lower the stress for dislocation generation from the grain boundaries or to ease the cross-slip close to the boundaries,and also to increase the number of dislocation sources.However,B-enhenced ductility is seriously affected by stoichiometry,the addition of a tertiary alloy element and heat treatment,etc..

关键词: Ni_3Al , null , null , null , null

COMPUTER SIMULATION OF GRAIN BOUNDARY STRUCTURES IN Ni_3Al

LIN Dongliang , (T.L.Lin) , CHEN Da Shanghai Jiaotong University , Shanghai , China Professor , Dept.of Materials Science , Shanghai Jiaotong University , Shanghai 200030 , China

金属学报(英文版)

The embedded atom type potentials and static relaxation method combined with steepest gra- dient computational technique have been used to simulate the grain boundary cohesive ener- gies,the distribution of electron density and stress field in the grain boundary,region,and oth- er related problems of[100],[110]and[111]symmetric tilt grain boundaries in Ni_3Al with different grain boundary geometrical index and composition.Their relations with the segrega- tion or boron,behaviors or the grain boundary,and especially the stoichiometrical effect of B induced ductility have also been studied and discussed.

关键词: Ni_3Al , null , null , null

INFLUENCE OF AUSTENITE STRENGTHENING ON MARTENSITIC TRANSFORMATION IN Fe-Mn-C ALLOYS

PAN Mu XU Zuyao (T.Y.Hsu) Shanghai Jiaotong University , Shanghai , China XU Zuy(T.Y.Hsu) , Professor , Dept.of Materials Science , Shanghai Jiaotong University , Huashan Road , Shanghai 200030 , China

金属学报(英文版)

The M_s temperature and the yield strength of austenite at M_s temperature have been meas- ured for five Fe-Mn-C alloys.The experimental results show that there is a linear relation- ship between them.The effect of the solution strengthening of austenite on martensite morphology is also studied.It is pointed out that there is a characteristic temperature T_c in austenite strengthening.Martensite morphology is mainly of dislocated laths when M_s>T_c, and is mainly of twinned plates when M_s

关键词: Fe-Mn-C alloy , null , null

INFLUENCE OF GRAIN SIZE AND ORDERING DEGREE OF PARENT PHASE ON SME IN A CuZnAl ALLOY CONTAINING BORON

WU Jianxin JIANG Bohong XU Zuyao(Hsu T.Y.) Shanghai Jiaotong University , Shanghai , China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A173—A178. Professor , Dept.of Materials Science , Shanghai Jiaotong University , Shanghai , China

金属学报(英文版)

The influence of grain size and ordering degree of the parent phase on the shape memory re- covery in a Cu-25.62Zn-3.97Al-0.0018B(wt-%)memory alloy is investigated.A mathematical relationship is set up between the recovery ratio and ordering degree,probabili- ty of atoms at their ordered sites,grain size,the thickness of the grain boundary affected re- gions,the stress during deformation,as well as the critical shear stress.Shape memory effect reaches a maximum with varying grain size and increases linearly with increasing ordering parameter,which agrees well with experimental results.

关键词: CuZnAl alloy , null , null , 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

CURRENT STATUS OF HIGH-RESOLUTION ELECTRON-MICROSCOPY AND ITS APPLICATIONS TO MATERIALS SCIENCE AND CONDENSED MATTER PHYSICS

材料科学技术（英文）

The present paper summarizes the current status of high resolution elect;on microscopy ( HREM) and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction, subnanometer level analysis, image simulation and image processing.

关键词: juxtaposed pentagonal antiprisms;two-dimensional quasicrystal;domain;boundary structures;close-packed phases;nanocrystalline materials;crystal-structure;copper oxidation;initial-stage;translational;symmetry;rotational symmetry

Current Status of High Resolution Electron Microscopy and Its Applications to Materials Science and Condensed Matter Physics

Douxing LI and Hengqiang YE (Laboratory of Atomic imaging of Solids , Institute of Metal Research , Chinese Academy of Sciences , Shenyang , 110015 , China)

材料科学技术（英文）

The present paper summarizes the current status of high resolution electron microscopy (HREM)and the applications of HREM to materials science and condensed matter physics. This review recounts the latest development of high resolution electron microscope, progress of HREM and the applications of HREM, including the crystal structure determination of microcrystalline materials and characterization of the local structure of the defects and nanostructured materials as well as qualitative and quantitative analysis of the grain boundaries, interfaces and interfacial reactions in the advanced materials by means of HREM in combination with electron diffraction,subnanometer level analysis, image simulation and image processing.

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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

The Coming of Materials Science

材料科学技术（英文）

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