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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 engineering,Nanjing university of science and Technology,Nanjing 210094,china 2 college of materials science and engineering,Southeast university,Nanjing 211189,china 1. Department of materials science and engineering 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

Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die

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Journal of materials science & Technology 2001年第1期17卷 135-136页

作者： He YANG and Zhichao SUN college of materials science and engineering, Northwestern Polytechnical university, Xi’an 710072, china NW Polytech Univ Coll Mat Sci & Engn Xian 710072 Peoples R China

The effect of the deformation condition on the axial compressive precision forming process of tube with curling die was investigated by using a rigid-plastic FEM. The results show that the forming accuracy depends mainly on geometric condition rp/d0, little on tube material properties and friction condition; the relative gap △/2rp of double-walled tubes obtained decreases with Increasing rp/d0, and there is a parameter k for a given to/do or rp/t0, when rp/d0 >k, △/2rp1.

关键词： Effect of Deformation Condition on Axial Compressive Precision Forming Process of Tube with Curling Die

Adsorption of polyelectrolyte on the surface of ZnO nanoparticles and the stability of colloidal dispersions

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science Bulletin 2005年第15期 36-41页

作者： LIUFU Shengcong, XIAO Hanning & LI Yuping college of materials science and engineering, hunan university, changsha 410082, china

The present study focuses on the adsorption of a polyelectrolyte, the component of which is a polymer of maleic anhydride sodium salt, on the surface of nanometric zinc oxide particles and the colloidal stability of aqueous dispersions. FTIR spectroscopic data provided evidence in support of hydrogen bonding and chemical interaction in the case of the polyelectrolyte-ZnO system. The adsorption iso-therms showed the influences of polyelectrolyte concentra-tion, pH and ionic strength on the adsorption. With the in-crease of pH the saturated adsorbed amount decreased, while the thickness of adsorption layer increased. The saturated adsorbed amount increased with increasing salt concentra-tion, and decreased with further increasing salt concentra-tion. It should be noted that in the presence of a CaCl2 solu-tion the adsorbed amount and the adsorption layer thickness were greater than those in the NaCl solution of the same concentration. The change of the absorbance of zinc oxide dispersions showed that the absorbance decreased slowly at high pH. There was a maximum point for the absorbance of the zinc oxide dispersions in the presence of various polye-lectrolyte concentrations. The change of dispersion stability resulted from the change of macromolecular chains confor-mation at the interface.

关键词： adsorption polyelectrolyte nanoparticles dispersion zinc oxide.

Performance tests of multi-metal zincate solutions with zinc sulfate and zinc oxide

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Rare Metals 2007年第S1期26卷 99-104页

作者： HUANG Xiaomei,and ZHANG Milin college of materials science and Chemical engineering,Harbin engineering university,Harbin 150001,china Harbin Engn Univ Coll Mat Sci & Chem Engn Harbin 150001 Peoples R China

Morphology of zinc alloy layer,from zincate solution with zinc sulfate and zinc oxide respectively,together with the consequent deposit was observed with SEM and back scattering electron *** was applied to analyze the components of zinc alloy layer and the interface of high-Si aluminum alloy substrate-zinc ***,the surface morphology of the zincated aluminum alloy after immersing in 3.5% NaCl solution for 7 d,is observed and the corrosion rate was ***,tension test is conducted to quantify the adhesion between high-Si aluminum cast substrate and the *** results show that,the zinc oxide contained zincating solution with sodium potassium tartrate and sodium citrate is a better one in multi-metal zincating *** zinc alloy layer from this one gets stable performance,perfect adhesion with deposit,and good corrosion resistance.

关键词： Al-Si alloy multi-metal zincating solution adhesion

Granular Effect of Fly Ash Repairs Damage of Recycled Coarse Aggregate

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Journal of Shanghai Jiaotong university(science) 2008年第2期13卷 177-180页

作者：李九苏肖汉宁龚建清 college of materials science and engineering Hunan University changsha university of science & Technology Changsha 410076China

Repairing effect of fly ash （FA） on damage of recycled coarse aggregate was evaluated by characteristics of pores and cracks in the vicinity of interracial transition zone （ITZ）. The interracial structure between the virgin aggregate and the attached old mortar was investigated and compared with ITZ of recycled aggregate concrete in the presence of FA or ultra-fine FA（UFA） by means of scanning electron microscope （SEM）. Diameter and plumpness frequency distribution of pores as well as width of the old ITZ, length of contacting points and cracks density were analyzed. The SEM results reveal that the diameter of pores is decreases significantly but pores plumpness increases. A decreased ITZ width and cracks density as well as an increased bonding zone length can also been observed, which indicates that FA or UFA repairs damage of recycled coarse aggregate due to its granular effect.

关键词： pores structure characteristics of interfaciial transition zone fly ash repairing effect

Characteristic atom arranging crystallogphy of alloy phases for Au-Cu system

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science china(Technological sciences) 2011年第6期54卷 1560-1567页

作者： XIE YouQing1,2,3,LIU XinBi1,2,3,PENG HongJian4,NIE YaoZhuang5,LI XiaoBo6 & LI YanFen1,2,3 1 School of materials science and engineering,Central South university,changsha 410083,china 2 Powder Metallurgy Research Institute,Central South university,changsha 410083 china 3 State Key Laboratory of Powder Metallurgy,Central South university,changsha 410083,china 4 School of Chemistry and Chemical engineering,Central South university,changsha 410083,china 5 School of Physical science and Technique,Central South university,changsha,410083,china 6 college of Mechanical engineering,Xiangtan university,Xiangtan 411105,china 1. School of materials science and engineering Central South University Changsha 410083 China2. Powder Metallurgy Research Institute Central South University Changsha 410083 China3. State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China4. School of Chemistry and Chemical Engineering Central South University Changsha 410083 China5. School of Physical Science and Technique Central South University Changsha 410083 China6. College of Mechanical Engineering Xiangtan University Xiangtan 411105 China

In this paper,it is pointed out that the descriptions of alloy phase structures are dependent on structural unit *** the systematic science of alloys(SSA),the alloy phase structures are described by means of the symmetry element sequence combining with characteristic atom *** is named the characteristic atom arranging structure,which can display the characteristic atoms at the lattice sites and the micro-inhomogeneity,besides the *** characteristic atom has its own characters:neighboring configuration,potential energy,volume and electronic *** micro-inhomogeneity of alloy phases can be described by concentrations and short-range ordered parameters of characteristic *** differences between the electronic structures of alloy phases and electronic structures of characteristic atoms in the alloy phases are also discussed.

关键词： systematic science of alloys Au-Cu system alloy phase structure micro-inhomogeneity

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 engineering, Northwestern Polytechnical university, Xi’an 710072, china 2. college of materials science and engineering, Henan university of science and Technology, Luoyang 471003, china 1. college of materials science 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.

Ti/Al_2O_3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

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Journal of materials science & Technology 1999年第3期15卷 271-275页

作者： Yimin LI(Powder Metallurgy Research Institute, Central-South university of Technology, changsha 410083, china)Ziqiao ZHENG(Department of materials science and engineering, Central-South university of Technology, changsha 410083, china) Cent S Univ Technol Powder Met Res Inst Changsha 410083 Peoples R China Cent S Univ Technol Dept Mat Sci & Engn Changsha 410083 Peoples R China

Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one

关键词： Al SHS Ti/Al2O3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

Electronic structures and properties of Ti, Zr and Hf metals

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Journal of Central South university of Technology 2001年第2期8卷 83-88页

作者： XIE You qing,PENG Kun,YANG Xin xin (Department of materials science and engineering, Central South university, changsha 410083, china) 1. Department of materials science and engineering Central South University 410083 Changsha China

The electronic structures of pure Ti, Zr and Hf metals with hcp structure were determined by one atom (OA) theory. According to the electronic structures of these metals,their potential curves, cohesive energies, lattice constants, elasticities and the temperature dependence of linear thermal expansion coefficients were calculated. The electronic structures and characteristic properties of these metals with bcc and fcc structures and liquids were also studied. The results show that the electronic structures of Ti, Zr and Hf metals are respectively [Ar](3d n) 0.481 0 (3d c) 2.085 7 (4s c) 1.000 0 (4s f) 0.433 3 , [Kr](4d n) 0.396 8 (4d c) 2.142 8 (5s c) 1.262 0 (5s f) 0.198 4 , [Xe](5d n) 0.368 0 (5d c) 2.041 4 (6s c) 1.406 6 (6s f) 0.184 0 . It is explained why the pure Ti, Zr and Hf metals with hcp and bcc structures can exist naturally, while those with fcc structure can not.

关键词： electronic structure Ti Zr Hf lattice constant cohesive energy crystal structure

Mixed boundary conditions for piezoelectric plates

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science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 755-761页

作者： GAO Yang 1 ,XU SiPeng 2 &ZHAO BaoSheng 3 1college of science,china Agricultural university,Beijing 100083,china 2college of engineering,Ocean university of china,Qingdao 266071,china 3 School of Mechanical engineering,university of science and Technology of Liaoning,Anshan 114044,china college of science China Agricultural University Beijing 100083 China college of engineering Ocean University of China Qingdao 266071 China School of Mechanical engineering University of Science and Technology of Liaoning Anshan 114044 China

For plate bending and stretching problems in piezoelectric materials,the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate mixed boundary conditions accurate to all order.A decay analysis technique is used to establish necessary conditions that the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the *** the case of axisymmetric bending and stretching of a circular plate,these decaying state conditions are obtained explicitly for the first time when the mixed conditions are imposed on the plate *** are then used for the correct formulation of boundary conditions for the interior solution.

关键词： boundary conditions piezoelectric plates mixed data bending problems stretching problems