检索结果-南通市图书馆

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 {2. and engineering, Northwestern Polytechnical university, Xi’an 710072. china 2. college of materials science and engineering, henan university of science and technology, luoyang 4.1003. china 1. college of materials {2. and engineering Northwestern Polytechnical University 710072 Xi’an China 2. college of materials science and engineering Henan University of Science and Technology 471003 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.

Effect of rare-earth element Sm on the corrosion behavior of Mg-6Al-1.2.-0.9Nd alloy

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第6期29卷 557-560页

作者： LI Quan’an,LI Xiaofeng,ZHANG Qing,and CHEN Jun School of materials science and {2.,henan university of science and technology,luoyang 4.1003.china School of materials science and {2. Henan University of Science and Technology Luoyang China

The effect of Sm（0 wt.%-2.wt.%） addition on the corrosion behavior of Mg-6Al-1.2.-0.9Nd alloy in 3.5 wt.% NaCl solution has been studied by static corrosion tests,corrosion morphology observation,corrosion scale and microstructure *** results show that,with the increasing of Sm content,the corrosion rate of the alloy decreases at first,then increases and reaches the valley at 0.5 wt.% *** reason is that the proper content of Sm addition can refine the precipitates and make the component and microstructure uniform,and therefore,it remarkably improves the corrosion resistance of the alloy.

关键词： magnesium alloys samarium corrosion behavior microstructure

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2. LIU GuoQuan2. LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic engineering college, Shandong Agricultural {2., Tai’an 2.1018, china 2.college of materials science and engineering, {2. of science and technology, Beijing 100083, china 3 college of Material science and engineering, Beijing {2. of Chemical technology, Beijing 10002., china Mechanical Electronic engineering college Shandong Agricultural University Tai’an 271018 China college of materials {2. engineering University of Science technology Beijing 100083 China college of Material science engineering Beijing University of Chemical Technology Beijing 100029 China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

Dynamic damage and stress-strain relations of ultra-high performance cementitious composites subjected to repeated impact

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2010年第6期53卷 1520-1525页

作者： LAI JianZhong1 & SUN Wei2.1 Department of materials science and {2.,Nanjing university of science and technology,Nanjing 2.0094,china 2.college of materials science and {2.,Southeast university,Nanjing 2.1189,china 1. Department of materials science and {2. Nanjing University of Science and Technology Nanjing 210094 China2. College of Materials Science and Engineering Southeast University Nanjing 211189 China

Ultra-high performance cementitious composites (UHPCC) were prepared by replacing 60% of cement with ultra-fine industrial waste *** dynamic damage and compressive stress-strain relations of UHPCC were studied using split Hopkinson pressure bar (SHPB).The damage of UHPCC subjected to repeated impact was measured by the ultrasonic pulse velocity *** show that the dynamic damage of UHPCC increases linearly with impact times and the abilities of repeated impact resistance of UHPCC are improved with increasing fiber volume *** stress waves on impact were recorded and the average stress,strain and strain rate of UHPCC were calculated based on the wave propagation *** effects of strain rate,fibers volume fraction and impact times on the stress-strain relations of UHPCC were *** show that the peak stress and elastic modulus decrease while the strain rate and peak strain increase gradually with increasing impact times.

关键词： ultra-high performance cementitious composites (UHPCC) split Hopkinson pressure bar (SHPB) repeated impact damage stress-strain

Melt-spun Al_(70-X)Si_(30)Mn_X (X=0,3,5,7,10) anode in lithium-ion batteries

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2009年第8期52卷 2288-2294页

作者： SUN ZhanBo1, LI XuePeng1, WANG XiaoDong1, HU Qing1, ZHAO MingShu1, ZHU YaoMin2. LI Yan2.& SONG XiaoPing1 1 School of science, State Key Laboratory for Mechanical Behavior of materials, Xi’an Jiaotong {2., Xi’an 710049, china 2.School of materials science and engineering, henan university of science and technology, luoyang 4.1003. china 1. School of science State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an 710049 China 2. School of materials science and {2. Henan University of Science and Technology Luoyang 471003 China

Al70-XSi30MnX (X=0, 3, 5, 7, 10, mol%) ribbons were prepared by melt spinning. A supersaturated solid solution of Si and Mn in fcc Al and some microstructures consisting of nano grains were obtained. Some alloys with nano-sized grains exhibited high discharge capacities and favorable cycle properties. The capacity of more than 400 mAh/g could be obtained in melt-spun Al67Si30Mn3 alloy after 2. cycles and more than 300 mAh/g after 40 cycles. Li/Si and Li/Al compounds in the anodes of pure Al and pure Si were not detected in Al-Si-Mn alloys inserted by Li. It is considered that the formation of the supersaturated solid solution and refinement of microstructures have prevented the alloys from the forming the compounds with superfluous Li. As a result, the electrochemical properties have been improved.

关键词： Al-Si-Mn alloy melt spinning microstructure electrochemical property

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology({2. science) 2009年第4期24卷 515-519页

作者：张津 School of materials science & {2. University of Science and Technology Beijing college of materials {2. & engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Effect of Fe Particle on the Surface Peeling in Cu-Fe-P Lead Frame

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology({2. science) 2006年第3期21卷 18-20页

作者：苏娟华 college of materials {2. and engineering Henan University of Science and Technology Luoyang 471003ChinaCollege of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072China

Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.

关键词： Cu-Fe-P lead frame surface peeling equivalent Stress equivalent strain

Preparation of semi-solid AlSi7Mg alloy slurry with big capability

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第6期29卷 642-645页

作者： LI Sha and MAO Weimin School of materials science and {2.,university of science and technology Beijing,Beijing 100083,china School of materials science and {2. University of Science and Technology Beijing Beijing China

Semi-solid AlSi7Mg alloy slurry was prepared by low superheat pouring and weak traveling-wave electromagnetic *** effects of pouring temperature and stirring power on the microstructure of AlSi7Mg alloy slurry were *** results show that the semi-solid AlSi7Mg alloy slurry of 5 kg can be *** new technology can save energy and make the pouring process *** the pouring temperature is decreased at a stirring power of 0.41 kW,the shape of primary α-Al grains gradually changes from dendritic-like to *** the alloy melt is poured at the temperature（630°C） with a certain superheat,the pouring process becomes easier,and the spherical microstructure of AlSi7Mg alloy slurry can be prepared by the weak traveling-wave electromagnetic *** the pouring temperature is 630°C,increasing the stirring power appropriately can result in better spherical primary α-Al grains,but if the stirring power is increased to a certain value（1.72.kW）,the shape of primary α-Al grains does not obviously improve when the stirring power is continually increased.

关键词： aluminum alloys metal forming semisolid slurry electromagnetic stirring microstructure

Effect of Stoichiometry on Properties of Rare-Earth-Based Hydrogen Storage Alloy for Nickel-Metal Hydride Secondary Battery

在线全文

学校读者我要写书评

暂无评论

Journal of materials science & {2. 2003年第1期19卷 90-92页

作者： Quan’an LISchool of materials science and {2., henan university of science and technology, luoyang 4.1003. chinaYungui CHEN and Mingjing TUDepartment of Metal materials, Sichuan university, Chengdu 610065, china henan Univ Sci & Technol Sch Mat Sci & Engn Luoyang 471003 Peoples R China Sichuan Univ Dept Met Mat Chengdu 610065 Peoples R China

Effect of stoichiometry on microstructures, electrochemical properties and PCT characteristics of the alloys MI（Ni0.71Co0.15-Al0.06Mn0.08）x （MI=Lanthanum-rich Michmetal, x=4.6;.2. have been investigated. The lattice constants a, c, and cellvolumes of non-stoichiometric alloys are bigger than those of the stoichiometric alloy. With the increasing stoichiometry x,the value of a decreases, and the value of c and cell volume increases except for those of the stoichiometric alloy; the plateaupressure of PCT curve, discharge capacity and cycling stability all increase. The alloy with x=5.2.shows the highest dischargecapacity and the best cycling stability among the studied alloys.

关键词： Hydrogen storage alloy Metal hydride electrode Rare earth Electrochemical property Stoichiometry

Preparation of Core-shell Cu-Ag Bimetallic Powder via Electroless Coating

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology({2. science) 2009年第4期24卷 637-639页

作者：徐锐 college of Metallurgy science and {2. Central South University college of Chemical and Pharmaceutical engineering Henan Universityof Science and Technology

A novel method of electroless silver coating on copper powders was reported, in which hydrazine was used as the reducing agent, and had some advantages such was used as inhibiting the substitution reaction and reducing consumption of copper powders. In the processes of sensitization and activation, AgNO3 replaces the conventional PdCl2. which solves the impurity of bath. Oxide film on the surface of copper powders was tested by chemical analysis. Ag element tested by XRD and XRF is in the form of Ago and exists on the surface of copper powders, which acts as catalyzer in reduction reaction. Morphology and composition of the coating were characterized by SEM and XRD respectively.

关键词： core-shell bimetallic powders electroless coating