HAN Yafang (Institute of Aeronautical Materials
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Beijing
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100095
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China)CHATURVEDIMC(University of Manitoba Winnipeg
,
Manitoba
,
Canada
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R3T2N2)
金属学报(英文版)
A high performance Ni-Al-Mo-B system cast Ni_3Al base alloy, named Alloy IC6, has been developed for advanced gas turbine blades and vanes. The alloy has high strength and ductility from room temperature to 1100℃ as well as excellent creep resistance over a wide temperature range of 760℃ to 1100℃ . The superior mechanical properties of this alloy.may be attributed to (1) solid solution hardening by the large amount of Mo addition , (2)second phase strengthening by γ-phase and other minor phases that precipitate in various temperature ranges, (3) rearrangement of γ-phase in the form of raft structure during creep deformation , (4) high-density misfit dislocation networks at the γ /γ' interfaces that form due to a high value ofγ /γ ' misfit .
关键词:
: Ni_3Al Alloy
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null
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null
Materials Science & Engineering C-Biomimetic Materials Sensors and Systems
The terminology of materials study inspired by biological systems or phenomena is analyzed at first. It is pointed that the term "bio-inspired" may be better than the terms "bionic" or "biomimetic", since the former is relatively easy to be accepted. The new trends of bio-inspired study of structural materials are analyzed in short. Some progress in bio-inspired design and processing of materials in this institute (IMRCAS) are summarized briefly in this talk, such as biomimetic design of worst bonding interface for composites; dumbell-like whiskers simulating animal bone; fractal tree reinforcement by mimicry of branched roots in soil; etc. The possibility of modification and recovery of materials by nonequilibrium bio-inspired treatment are further explored, including the nonequilibrium process under transient heating, dissipative structure and self-organization process of open system, inspiration by living process, influence of high intensive electropulsing on the working Life of materials, a possible way of fatigue recovery of materials and the healing effect of electropulsing in metals. Some tentative practice in biomaterial modification are also studied such as the reformed bamboo reinforced aluminium laminates, etc. A discussion on the methodology of bio-inspired study of materials consists briefly in the last part of the talk. (C) 2000 Elsevier Science S.A. All rights reserved.
关键词:
bio-inspired;bionic;biomimetic;structural materials;composites
Journal of Applied Physics
The dependence of yield strength, uniform elongation, and toughness on grain size in metallic structural materials was discussed. The toughness is defined as the product of yield strength and uniform elongation. The yield strength versus grain size can be well described by the Hall-Petch relation; however, the uniform elongation versus grain size is not well understood yet. A simple model involving the densities of geometrically necessary dislocations and statistically stored dislocations was proposed to estimate the uniform elongation versus grain size. Existing data for low carbon steels and aluminum indicate that, in the grain size less than 1 mu m, the materials usually exhibit high strength and low uniform elongation and, in the grain size greater than 10 mu m, the materials usually exhibit low strength and high elongation; in either case the toughness is low. However, in the grain size of several micrometers, the toughness is the highest. It is suggested that we should pay more attention to develop the metallic materials with grain size of several micrometers for structural applications. (c) 2007 American Institute of Physics.
关键词:
nanocrystalline copper;nanostructured metal;steels;deformation;ductility;law
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
