Z. Bian
,
G. He and G.L. Chen (State Key Laboratory for Advanced Metals and Materials
,
University of Science and Technology Beijing
,
Beijing 100083
,
China) J. Lu
,
D.J. Chen
,
G.C. Tu
,
G.J. Chen and X.J. Hu (Shougang Metallurgical Research Institute
,
Beijing 100085
,
China)
金属学报(英文版)
Al80Ni6 Y8 Co4 Cu2 amorphous ribbons were isothermally annealed and a mixed structure consisting of α-Al particle with a size of less than 15nm and Al3Ni compound with a size of about 30nm was obtained. The crystallization kinetics of Al80Ni6 Y8 Co4 Cu2 amorphous alloy shows that the precipitation of α-Al particles is the growth process controlled by diffusion of the solute elements rejected from the growing crystals. By quenching at different cooling rates, a mixed structure consisting of nanoscale α-Al particles and the remaining glass matrix or structure consisting of nanoscale particle (Al phase or Al3Ni compound) with a size of about 100nm was formed. The addition of Co elements and Cu elements to Al-Ni-Y alloy systems increases the glass formation ability of the alloy and the thermal stability of the supercooled liquid region against crystallization, which results from significant difference of atomic size, strong bonding nature among constituent elements and the low diffisivity of the solute elements due to the concentration gradient in the growing front of crystals.
关键词:
a mixed structure
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null
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null
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null
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null
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null
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null
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
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
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null
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null
,
null
,
null
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null
,
null
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null
,
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Communications in Theoretical Physics
By using the theory of pressure-induced shifts and the eigenfunctions at normal and various pressures obtained from the diagonalization of the complete d(3) energy matrix adopting C-3v symmetry, g factors of the ground state of ruby and their pressure-induced shifts have been calculated. The results are in very good agreement with the experimental data. For the precise calculation of properties of the ground state, it is necessary to take into account the effects of all the excited states by the diagonalization of the complete energy matrix.
关键词:
crystal fields;g factors;ruby;high-pressure effects
Materials Characterization
Segregation of yttrium induces the formation of Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y microdomains, with L1(2)- and L1(0)-like ordered structures, in ZrO2-6mol%Y2O3 ceramics in both the sintered and annealed states. The compositions of precipitates such as (chi L), (chi S), (chi SS), and small precipitates formed inside XL, in Cu-11.88Al-5.06Ni-1.63Mn-0.96Ti (wt.%) shape memory alloys have been determined. Under electron beam irradiation, four types of dynamic behavior of the G.P. zones were observed in the Al-6.58Zn-2.33Mg-2.40Cu (wt.%) alloy. The G.P. zone and "G.P. zone-like" defect structures were also distinguished. Lattice distortion profile in the GaAs/InxGa1-xAs superlattice and two-dimensional lattice distortion around a 60 degrees dislocation core in the InAs(x)P(1-)x/InP superlattice were determined. (C) Elsevier Science Inc., 2000. All rights reserved.
关键词:
shape-memory alloys;zirconia;phase;ti;diffraction;crystal
袁诗璞
电镀与涂饰
氯化钾镀锌液配方中,氯化钾的含量通常是200～ 250 g/L,但在生产维护时分析镀槽中的氯化钾有时高达近400 g/L.认为以EDTA滴定法及硝酸银滴定法分别测总锌与总氯,然后从总氯中减去氯化锌所占氯的量而计算出氯化锌含量的常规化验方法有一定的局限性,尤其不适用于大生产已久的镀液.介绍了控制氯化钾含量的方法:先调整pH,接着通过赫尔槽试验分析并调整锌离子浓度,然后分析并调整光亮剂及硼酸,最后通过试验确定氯化钾补加量.
关键词:
镀锌
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氯化钾
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分析
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调整
,
赫尔槽试验
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
,
null
,
null
Journal of Nuclear Materials
Due to its inert reactivity with almost elements, He-3 produced from tritium decay has extremely detrimental effects on the tritide. To refrain from this He-3-induced damage, an efficient way is to increase the stability of He-3 in metal tritide by alloying. Using a first-principles discrete variational method in two cluster models, one for a low He-3 concentration and the other for a high He-3 concentration, the authors study the alloying effect of 3d and 4d transition metals on the stability of He-3 in TiT2 system. It is found that the preferring and metastable sites of He-3 are affected by He-3 concentration : He-3 prefers to stay at original tetrahedral interstitial site when He-3 concentration is low but moves to octahedral site when He-3 concentration is high enough. A criterion of alloying effect is proposed, according to which Nb, Y, Zr, Pd, Ru, Tc, Rh, Cr, Mo and Ag are suggested to be the beneficial alloying elements for increasing the stability of He-3 in the alloyed TiT2 with a low He-3 concentration and Y, Nb, Mo, Zr, Cr, Tc, Ru, Rh and Cu for that with a high He-3 concentration. Our results of alloying effect are supported by the positron annihilation spectroscopy (PAS) measurements for He-implanted Ti, TiMoYAl and TiZrYAl films. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
electronic population analysis;molecular wave functions;hydrogen;storage alloys;intermetallic hydride;bubble formation;iron clusters;helium;tritides;lcao;overlap
Express Polymer Letters
The state-of-art and key problems of carbon nanotube (CNT) based polymer composites (CNT/polymer composites) including CNT/polymer structural composites and CNT/polymer functional composites are reviewed. Based on the results reported up to now, CNTs can be an effective reinforcement for polymer matrices, and the tensile strength and elastic modulus of CNT/polymer composites can reach as high as 3600 MPa and 80 GPa, respectively. CNT/polymer composites are also promising functional composite materials with improved electrical and thermal conductivity, etc. Due to their multi-functional properties, CNT/polymer composites are expected to be used as low weight structural materials, optical devices, thermal interface materials, electric components, electromagnetic absorption materials, etc. However, the full potential of CNT/polymer composites still remains to be realized. A few key problems, such as how to prepare structure-controllable CNTs with high purity and consistently dependable high performance, how to break up entangled or bundled CNTs and then uniformly disperse and align them within a polymer matrix, how to improve the load transfer from matrix to CNT reinforcement, etc, still exist and need to be solved in order to realize the wide applications of these advanced composites.
关键词:
polymer composites;carbon nanotubes;mechanical properties;electrical;properties;thermal properties
