N. Wang and B. Wei (Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)(Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The Ag-50wt%Cu hypereutectic alloy was solidified in a 3m drop tube. It is .revealed that with the decrease of droplet size, the strnctural morphology transformed from the dendrites with long trunk and thin short secondary arms to fine dendritic structures.The calculations based on LKT dendritic growth model indicate that dendritic growth is dominantly controlled by solute diffusion within the whole undcreooling regime.However, the influence of thermal diffusion-controlled growth becomes stronger above a critical undercooling about 268K. The refinement of dendritic structure is caused by large amounts of nuclei within droplet. Moreover, it is estimated that when droplet diameter is smaller than 300μm, the undercooling and growth velocity are fanger than 268K and 290mm/s respectively, while the solute impping effect may occur. Compared with Ag-15wt%Cu hypoeutectic alloy, there is no evident feature of dendritic-toequiaxed transition for Ag-50wt%Cu hypereutectic alloy, which is consistent with the calculation results of dendritic breakap time.Keuwords: Ag-Cu alloy; rapid solidification; undercooling; dendritic growth
关键词:
Ag-Cu alloy
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null
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null
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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
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null
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null
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Shaoxiong ZHOU
材料科学技术(英文)
The discovery of the first Fe-based ferromagnetic amorphous alloy in 1966 had made an impact on conventional magnetic materials because of its unique properties. Since then, a number of amorphous magnetic materials have been successfully developed and used in a wide variety of applications. A brief review of R & D activities on amorphous soft magnetic materials in China is given from the beginning to the present in a somewhat chronological order, followed by a brief introduction to their applications on electric and electronic industries. An analysis and a prospect of Chinese market of such amorphous materials are also presented.
关键词:
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.
关键词:
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
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null
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null
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