Author X.A. Zhang1)
,
H.Q. Xia1)
,
Z.T. Wu1)
,
Y.F. Han1)
,
R. Shi2) and G.X. Hu2) \= 1) Mechanical Properties Laboratory
,
Beijing Institute of Aeronautical Materials
,
Beijing 100095
,
China2) The State Education Commission Open Research Laboratory for High Temperature
金属学报(英文版)
Materials and Testing, Shanghai Jiao Tong University, Shanghai 200030, ChinaManuscript received 18 October 1998 The threestage creep behavior of DD3 single crystal superalloy had been studied. The results show that the creeprupture properties of DD3 single crystal satisfy the requirements for high performance turbine blade application. The influence of crystal orientation on the creeprupture property of DD3 single crystal was tested and discussed. An engineering criterion to evaluate the regimes of secondary and tertiary creep is proposed, and this method gives a reasonable result for practical applications. The fractography and TEM micrography of the tested specimens had been studied, and it is determined that the glidecontrolled creep is the basic creep mechanism of DD3 single crystal at intermediate temperature, but the thermally activated processes become dominant at higher temperature.
关键词:
threestage creep curve
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null
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null
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G.Q. Zhang
金属学报(英文版)
The status of research, development of superalloys and materials processing & fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superalloys for aero-engine disks and rings, and powder metallurgy (PM) superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.
关键词:
superalloy
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null
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Runhua Qin
材料科学技术（英文）
A novel salt-assisted low temperature solid state method using CoCl2?6H2O, FeCl3?6H2O and NaOH as pre-
cursor and using NaCl as a dispersant to synthesize high surface area CoFe2O4 nanoparticles, has been
investigated. The effects of the molar ratio of added salt and calcination temperature on the characteristics of
the products were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating
sample magnetometer (VSM) and Brunauer, Emmett and Teller (BET) surface area analysis. Results showed
that the introduction of leachable inert inorganic salt as a hard agglomeration inhibitor in the mixture precursor
led to the formation of high dispersive CoFe2O4 nanoparticles; and the increase in specific surface area from
28.28 to 73.97 m2/g, and the saturation magnetization is 84.6 emu/g.
关键词:
Low temperature solid state reaction
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盐助
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钴铁氧体
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纳米粒子
Nanotechnology
A highly porous and nanostructured CuO-ZnO composite has been synthesized for the sensing electrode of a solid-state electrochemical sensor for the high-temperature detection of carbon monoxide. The sensing electrode is made of ZnO nanotetrapod supported CuO nanoparticles. The ZnO nanotetrapods form a three-dimensional interconnected network, leading to a highly porous electrode. The ZnO nanotetrapods on which the CuO nanoparticles are highly dispersedly supported have a high surface-to-volume ratio while maintaining thermal stability at high temperature. Our approach provides an inexpensive route for large-scale production of porous and nanostructured electrodes, which increases the sensitivity of solid-state electrochemical sensors for on-line gas detection at high temperature.
关键词:
carbon-monoxide oxidation;zinc oxide catalysts;gas sensors;methanol
Author S.T. TU
,
J.M. Gong and X. Ling Nanjing University of Chemical Technology
,
Nanjing 210009
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
In order to interpret the test results of crossweld specimens for application in practical welded components, the present paper studies the high temperature behavior of laboratory cross weld specimens in terms of the uniaxial material tests and numerical simulations. It is found that the crossweld specimen may be used for the high temperature strength assessment, but can hardly be used for life assessment of the practical welded components, which depends on the loading conditions of the components.
关键词:
high temperature
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null
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null
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Materials Letters
By using a novel high-pressure, high-temperature method, perovskite oxides of La1-xNaxTiO3 (x = 0.05, 0.1-0.8) with mixed valence state were synthesized. XRD analysis shows a cubic cell for the samples. Cell volumes of the samples with 0.1 less than or equal to x less than or equal to 0.5 decreases as x increases, and the cell Volume for x = 0.05 is smaller than that for x = 0.1. XPS of surface and EPR measurements indicate that Ti ions are of mixed valence of +3 and +4 and that A-cations vacancies exist in the samples. As x increases, the amount of Ti3+ ions decreases and the amount of A-cations vacancies increases. The valence state of Ti ions can be altered by changing both pressure and temperature. (C) 2000 Elsevier Science B.V. All rights reserved.
关键词:
high-pressure and high-temperature synthesis;XPS;EPR;mixed valence;oxides;electrical-properties
