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Crystallization in Zr_(60)Al_(15)Ni_(2.) bulk metallic glass subjected to rolling at room temperature

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science china(Technological sciences) 2010年第1期53卷 278-283页

作者： YAN ZhiJie,YAN Jun,HU Yong & DANG ShuE school of materials {2. and engineering,taiyuan university of {2. and technology,taiyuan 03002.,china school of materials {2. and engineering Taiyuan University of Science and Technology Taiyuan China

The microstructure evolution of Zr60Al15Ni2. bulk metallic glass during rolling at room temperature is investigated by differential scanning calorimetry(DSC),high-resolution transmission electron microscopy(HRTEM) and selected area electronic diffraction(SAED).The HRTEM images show that shear bands are produced in the rolled specimens,indicating the essence of inhomogeneous deformation due to rolling,and that there exist nanocrystals with size of about 5-10 nm in the transition regions between the shear bands and the undeformed matrix in the rolled specimens with deformation degrees of 80% and 95%.Based on the polyhedral structure model and the shear transformation zone(STZ) theory,the influence of viscous flow,free volume,viscosity and the stress situation on the crystallization behaviors in the metallic glass during rolling is discussed.

关键词： metallic glasses plastic deformation nanocrystallization free volume

Chemical Extraction Preparation of Delithiated Cathode materials of Li-ion Battery

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Journal of Wuhan university of technology({2. science) 2009年第6期24卷 863-866页

作者：闫时建 school of materials {2. and engineering Taiyuan University of Science and Technology

A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2.2.8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.

关键词： chemical extraction delithiated cathode material Li-ion battery

Phase transition in the Zr_(60)Al_(15)Ni_(2.) bulk metallic glass subjected to rolling at room temperature

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science china(Technological sciences) 2006年第6期49卷 655-662页

作者： YAN Zhijie1, 2. LI Jinfu1, ZHOU Yaohe1 & WU Yanqing3 1. State Key Laboratory of Metal Matrix Composites, school of materials {2. and engineering, Shanghai Jiao Tong university, Shanghai 2.0030, china 2. school of materials science and engineering, taiyuan university of {2. and technology, taiyuan 03002., china 3. school of Environmental {2. and engineering, Shanghai Jiao Tong university, Shanghai 2.0030, china State Key Laboratory of Metal Matrix Composites School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai China school of materials {2. and engineering Taiyuan University of Science and Technology Taiyuan China school of Environmental science and {2. Shanghai Jiao Tong University Shanghai China

The microstructure evolution of the Zr60Al15Ni2. metallic glass during rolling at room temperature is investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC); high-resolution transmission electron microscopy (HREM). The results show that the values of full width at half maximum (FWHM) of the XRD patterns; exothermic enthalpy ΔH of DSC plots do not monotonically change with the variation of deformation degrees . As is not large than 2.%, the values of FWHM; ΔH are lower than that of the as-cast state. When reaches 30%, the values of FWHM; ΔH become larger than that of the as-cast state, while their values begin to decrease again as reaches about 85%. These results indicate that the reversible transitions between ordered; disordered atomic configurations occur during rolling, which is further verified by the HREM images. The reversible phase transition can be explained by the competition between the diffusion controlled reordering; shear-induced disordering during rolling.

关键词： metallic glasses, plastic deformation, phase transformations, shear bands.

Effects of Cu^(2.) on characteristic of SV currents

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science china Chemistry 2006年第6期49卷 560-564页

作者： ZHANG Liping1,2.& YANG Pin1 1. Key Laboratory of Chemical Biology and Molecular engineering of Ministry of Education, Institute of Molecular science, Shanxi {2., taiyuan 030006, china 2. Institute of Environment science, taiyuan {2. of science and technology, taiyuan 03002., china Key Laboratory of Chemical Biology and Molecular engineering of Ministry of Education Institute of Molecular Science Shanxi University Taiyuan China Institute of Environment science Taiyuan University of Science and Technology Taiyuan China

Applying the patch-clamp technique to vacuoles from Radish we studied the effects of Cu2. on Slow Vacuolar (SV) current’s characteristic. Our results show that Cu2. in bath solution at higher concentration inhibits SV currents and the percentage of inhibition increases with increasing concentration and changes with different voltage. When at lower concentration, Cu2. significantly promotes the SV currents and the promotion ratio decrease with increasing voltage. At the same time, the time constants of activation become lesser after adding Cu2.. These results show that there may be some Cu2. binding sites on SV channels and binding to which can change SV current’s characteristic.

关键词： the patch-clamp technique, vacuolar, Cu2., SV channel.

Optimization of thermomechanical processes in Cu-Cr-Zr lead frame alloy using neural networks and genetic algorithms

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science china(Technological sciences) 2005年第5期48卷 510-520页

作者： SU Juanhua1,2. LIU Ping2. DONG Qiming2.& LI Hejun1 1. College of materials science and {2., Northwestern Polytechnical university, Xi’an 710072. china 2. College of materials science and {2., Henan university of science and technology, Luoyang 471003, china College of materials science and {2. Northwestern Polytechnical University Xi’an China College of materials science and {2. Henan University of Science and Technology Luoyang China

The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model, genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties. The good generalization performance and optimized results of the integrated model are achieved.

关键词： Cu-Cr-Zr alloy, thermomechanical processing optimization, artificial neural network, genetic algorithms.

Microstructure and Mechanical Properties of Ultrafine Grained Mg15Al Alloy Processed by Equal-channel Angular Pressing

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Journal of Wuhan university of technology({2. science) 2010年第2期25卷 238-242页

作者：王红霞梁伟 College of materials science and {2. Taiyuan University of Technology Key Laboratory of Interface science and engineering in Advanced {2. Ministry of Education Taiyuan University of Technology

An as-cast magnesium alloy with high Al content Mg15Al was subjected to equal-channel angular pressing （ECAP） through a die with an angle of φ= 90？ at 553 K following route Bc. It is found that the network β-Mg17Al12.phases in the as-cast Mg15Al alloy are broken into small blocks and dispersed uniformly with increasing numbers of pressing passes. Moreover, many nano-sized Mg17Al12.particles precipitate in the ultra-fine α-Mg matrix. The grains are obviously refined. However, the grain structure is inhomogeneous in different areas of the alloy. The average size of the primary phase α-Mg is reduced to about 1 μm while grains of around 0.1-0.2.μm are obtained in some two-phase areas. With additional ECAP passes （up to 8）, coarsening of the grains occurs by dynamic recovery. Room temperature tensile tests show that the mechanical properties of Mg15Al alloys are markedly improved after 4 ECAP passes. The ultimate tensile strength and elongation to failure increase from 150 MPa to 2.9.3 MPa and from 0.05% to 7.4%, respectively. Compared with that after 4 passes, the elongation to failure of the alloy increases but the strength of the alloy slightly decreases after 8 ECAP passes. Fracture morphology of the ECAP-processed alloy exhibits dimple-like fracture characteristics while the as-cast alloy shows quasi-cleavage fractures.

关键词： high-aluminum Mg Alloy β-Mg17Al12.phase ultra-fine grained microstructure mechanical properties equal-channel angular pressing

Improving the Wear Resistance of AZ31B Magnesium Alloy by Laser Cladding with Al-Si/Al_2._3-TiO_2.Powders

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稀有金属材料与工程 2011年第S4期40卷 169-173页

作者： Cui Zeqin1,2.Wang Wenxian1,2.Wu Hongliang1,Xu Bingshe1,2.1Key Laboratory of Interface science and engineering in Advanced {2. (taiyuan university of technology),Ministry of Education,taiyuan 03002.,china 2.ollege of {2. science and engineering,taiyuan university of technology,taiyuan 03002.,china taiyuan Univ Technol Coll Mat Sci & Engn Taiyuan 030024 Peoples R China taiyuan Univ Technol Minist Educ Key Lab Interface Sci & Engn Adv Mat Taiyuan 030024 Peoples R China

To improve the wear resistance of magnesium alloy,the laser surface cladding of AZ31B magnesium alloy with Al-12.% Si and Al2.3-40 % TiO2.composite powders (in the wt.% ratio of 10:1,6:1,4:1) were investigated by using a 5kW continuous wave CO2.laser.A detailed microstructure and phase analysis of the surface modified layer were studied by optics microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy (EDS),X-ray diffraction(XRD).The microstructure of the surface modified layers mainly consist of Al-Mg matrix,dendrite precipitates and Al2.3,TiO2.ceramic *** microhardness of the surface layer were measured and wear resistance property were evaluated in *** average microhardness of the surface layers were significantly improved to 2.0HV0.05 as compared with 50HV0.05 of the AZ31B *** results showed that the wear resistance of the laser surface modified samples was considerably improved as compared as the as-received specimen.

关键词： AZ31B magnesium alloy laser cladding Al-Si/Al2.3-TiO2 powders wear resistance

Synthesis of nano onion-like fullerenes by using Fe/Al_2._3 as catalyst by chemical vapor deposition

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Chinese science Bulletin 2009年第1期54卷 137-141页

作者： LIU XuGuang1,2.WANG CunJing1,2.YANG YongZhen1,3,GUO XingMei1,2.WEN HaiRong1,2.& XU BingShe1,3 1 Key Laboratory of Interface science and engineering in Advanced {2.,Ministry of Education,taiyuan university of Tech-nology,taiyuan 03002.,china 2.College of Chemistry and Chemical engineering,taiyuan university of technology,taiyuan 03002.,china 3 College of {2. science and engineering,taiyuan university of technology,taiyuan 03002.,china Key Laboratory of Interface science and engineering in Advanced {2. Ministry of Education Taiyuan University of Technology Taiyuan China College of Chemistry and Chemical engineering Taiyuan University of Technology Taiyuan China College of materials science and {2. Taiyuan University of Technology Taiyuan China

Nano-carbon materials were synthesized by the catalytic decomposition of acetylene at 400℃ by using Fe/Al2.3 as catalyst. The product was refluxed in 36% concentrated HCl at 60℃ for 48 h in order to re-move the catalyst support. The samples were examined by scanning and high resolution transmission electron microscopy,energy dispersive spectroscopy and X-ray diffraction. The results show that nano onion-like fullerenes encapsulating a Fe3C core were obtained. These had a structure of stacked graphitic fragments,with diameters ranging from 15―50 nm. When the product was further heat-treated at 1100℃ for 2.h,nano onion-like fullerenes with a clear concentric graphitic layer structure were obtained. The growth mechanism of nano onion-like fullerenes encapsulating metal cores is suggested to follow a vapor-solid growth model.

关键词：纳米碳材料化学蒸发沉积作用合成增长机制

Ni60-SiC Coating Prepared by Plasma Spraying, Plasma Re-melting and Plasma Spray Welding on Surface of Hot Forging Die

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Journal of Wuhan university of technology({2. science) 2011年第4期26卷 715-718页

作者：王洪福 school of Mechanical engineering and Automation North University of China

In order to produce the hear-resistant inner layer of hot-forging die, plasma spraying and plasma re-melting and plasma spray welding were adopted. Substrate material was W6Mo5Cr4V2. including 10%, 2.%, 30% SiC ceramic powder used as coating material to obtain different Ni-based SiC alloys coating. Micro-structure and micro-hardness analysis of the coating layer were followed, as well as thermophysical properties for the coating layer were measured. The experimental results show that the coating prepared with 70% Ni60, 30% SiC powder has best properties with plasma spray welding, in which the micro-hardness can achieve 1100 HV, meanwhile can improve the thermal property of hot-forging die dramatically.

关键词： hot forging die plasma spraying plasma re-melting plasma spray welding thermo- physical properties