ZHANG Yue
,
CHU Wuyang
,
XIAO Jimei(Department of Materials Physics
,
University of Science and Technology Beijing
,
Beijing 100083
,
China) OUYANG Shixi
,
YUAN Runzhang(State Key Laboratory for Synthesis and Processing of Advanced Materials.Wuhan University of Technology
,
Wuhan 430070
,
China)
金属学报(英文版)
For alloy Ti-24Al-11Nb,stress corrosion cracking(SCC) in methanol solution and hydrogen induced cracking(HIC) during dynamic charging at room temperature have been studied.Experiment has shown that the normalised threshold stress intensities of SCC failure for various microstructures are KISCC/KC =0.53 0.69 and the threshold value for SCC arresting KISCC/ KIC=0.61-0.79.The threshold values of HIC during dynamic charging are close to that of SCC,but da/dt or fracture time of HIC is one to three orders of magnitude smaller or longer than that of SCC,respectively.The.fracture surface for HIC is also different from that for SCC.For the Ti-24Al-Nb alloy-methanol systein,a kind of inierphase SCC has been found For the microstructures resulting from furnace cooling,SCC initiated and propagated preferentially along theα2/βinterphase boundaries,displaying the microstructure on the fracture surface of SCC.However,there is no interphase SCC for the microstructure resulting from air cooling.
关键词:
:Ti-24Al-11Nb
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null
,
null
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null
F.H. Froes(IMAP
,
University of Idaho
,
Moscow
,
ID 838443026
,
USA Manuscript received 26 August 1996)
金属学报(英文版)
The synthesis, processing and mechanical properties of the light metals, aluminum,magnesium and titanium Produced by advanced techniques are reviewed. Synthesis techniques to be addressed will include rapid solidification, spray deposition, mechanical alloying, plasma Processing and vapor deposition.
关键词:
:synthesis/processing
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null
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null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
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Advanced Materials
Popularization of portable electronics and electric vehicles worldwide stimulates the development of energy storage devices, such as batteries and supercapacitors, toward higher power density and energy density, which significantly depends upon the advancement of new materials used in these devices. Moreover, energy storage materials play a key role in efficient, clean, and versatile use of energy, and are crucial for the exploitation of renewable energy. Therefore, energy storage materials cover a wide range of materials and have been receiving intensive attention from research and development to industrialization. In this Review, firstly a general introduction is given to several typical energy storage systems, including thermal, mechanical, electromagnetic, hydrogen, and electrochemical energy storage. Then the current status of high-performance hydrogen storage materials for on-board applications and electrochemical energy storage materials for lithium-ion batteries and supercapacitors is introduced in detail. The strategies for developing these advanced energy storage materials, including nanostructuring nano-/microcombination, hybridization, pore-structure control, configuration design, surface modification, and composition optimization, are discussed. Finally, the future trends and prospects in the development of advanced energy storage materials are highlighted.
关键词:
lithium-ion batteries;carbon nanotube electrodes;enhanced hydrogen;storage;metal-organic frameworks;double-layer capacitors;n-h system;carbide-derived carbons;ammonia borane dehydrogenation;ordered;mesoporous carbons;high-rate performance
Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science
Friction stir processing (FSP), developed based on the basic principles of friction stir welding (FSW), a solid-state joining process originally developed for aluminum alloys, is an emerging metalworking technique that can provide localized modification and control of microstructures in near-surface layers of processed metallic components. The FSP causes intense plastic deformation, material mixing, and thermal exposure, resulting in significant microstructural refinement, densification, and homogeneity of the processed zone. The FSP technique has been successfully used for producing the fine-grained structure and surface composite, modifying the microstructure of materials, and synthesizing the composite and intermetallic compound in situ. In this review article, the current state of the understanding and development of FSP is addressed.
关键词:
strain-rate superplasticity;cast nial bronze;al-mg-zr;low-temperature;superplasticity;nickel-aluminum bronze;particle-size ratio;mechanical-properties;microstructural modification;magnesium alloy;grain-refinement
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
,
null
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
A lot of non-equilibrium high technologies have recently been developed in materials processing, such as spray forming; metal atomization by electric fluid dynamics; self-propagating high temperature synthesis; in situ contact reaction process in melt for making composites and electropulsing effect on structure modification and damage reversal etc. A series of non-equilibrium thermophysical problems arise consequently with these high technologies. Not only the real-time measurements are difficult to deal with, but also the principle analyses need to be treated carefully. It would be found that some of the normal thermophysical rules should be evaluated again, when the thermophysical processes under extreme conditions are further studied. Some possible ways for solving these abnormal thermophysical problems are tentatively suggested in this paper, such as the reconstruction of governing functions; the simplified treatment of complex processes and making use of the rules of other disciplines etc. It is known from these examples that a series of non-equilibrium thermophysical problems arising from recent high technologies of materials processing are remained to be actively studied. It gives a virgin land for thermophysicists to explore. (C) 2000 Elsevier Science S.A. All rights reserved.
关键词:
biomimetic;materials processing;non-equilibrium;thermophysical;problems
M. Bahgat
,
null
材料科学技术(英文)
Iron carbides are very promising metallurgical products and can be used for steelmaking process, where it plays as an alternative raw material with significant economic advantages. Also it has many other applications, e.g. catalysts, magnets, sensors. The present review investigates the different properties and uses of the iron carbides. The commercial production and the different varieties for the iron carbides synthesis (gaseous carburization, mechanochemical synthesis, laser pyrolysis, plasma pyrolysis, chemical vapor deposition and ion implantation) were reviewed. Also the effect of different factors on the carburization process like gas composition, raw material, temperature, reaction time, catalyst presence and sulfur addition was indicated.
关键词:
Iron carbides
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null
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null
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D M DIMIDUK(Wright-Laboratory
,
Materials Directorate
,
WL/MLLM
,
Wright-Patterson AFB
,
OH45433-7817
,
USA)P R SUBRAMANIAN and M G MENDIRATTA (UES
,
Inc.
,
Dayton
,
OH 45432
,
USA)
金属学报(英文版)
Since the late 1980's there have been a number of research efforts aimed at exploring and developing the refractory intermetalllic materials for service at temperatures which compete with the nickel-based superalloys in structural applications. These efforts have documented the physical and mechanical properties of a broad set of compositions. However, only in the last three years have these efforts yielded sufficient experimental results on single selected systems to suggest that damage tolerance, creep resistance and oxidation resistance may be obtained and controlled simultaneously. These findings led to alloy development concepts and approaches which are currently under investigation and are expected to lead to research focused on a smaller set of alloys. An overview of selected alloy development strategies and resulting structural properties is presented herein.
关键词:
: refractory intermetallics
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null
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