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Interfacial structure and joint strengthening in arc brazed galvanized steels with copper based filler

中国有色金属学会会刊：英文版 2006年第2期16卷 397-401页

作者：李瑞峰于治水祁凯 Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang 212003 China College of Materials Engineering Shanghai Univers ity of Engineering Science Shanghai 200336 China

Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.

关键词：镀锌钢 CuSi3 TIG MIG 电弧钎焊接头强度显微结构

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Ti/Fe EUTECTIC REACTION PROCESS

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 614-617页

作者： WU Mingfang MA Cheng YANG Min Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang 212003 China School of Materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

To obtain satisfactory joining between titanium alloys end stainless steel, it is of great significance to study the process of Ti-Fe eutectic reaction. The preliminary studies about the liquid forming, spreading end the structure of the contact reaction between pure Ti and pure Fe are carried out at 1 120℃ for different holding times in high-frequency induction heated vacuum furnace. The results show that for Fe（particle-like）/Ti（plate-like） contact reaction couples, owing to Fe＇s higher density then titanium＇s, the Fe/Ti eutectic reaction develops in the thickness direction of plate-like Ti, named ＂deposition effect＂. Then the eutectic reaction can be realized without the inter-diffusion between Ti end Fe atoms, so the formation rate of the liquid phase is very quick. For Ti （particle-like）/ Fe （plate-like） contact reaction couples, the eutectic reaction has a strong direction, i.e. the eutectic liquid is formed mostly at the Ti side, which leads to much dissolution of Ti particle end very little dissolution of the Fe base metal. It can be seen that the diffusion rate of Fe in Ti determines the whole process of the eutectic reaction, behaved as that the dissolution rate of Ti （particle-like）/ Fe （plate-like） is much lower then that of Fe（particle-like）/Ti（plate-like）, end the dissolution rate of Ti obeys the square root law. Whatever means the Ti, Fe are assembled by, only dissolution process can be founded, the spread phenomena is unobvious, which is concerned with the formation of the inter- metallic compounds end the ＂deposition effect＂ of Fe.

关键词： Ti Fe Eutectic reaction Dissolution Spread

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Effect of cooling rate on evolution of superconducting phases during decomposition and recrystallization of (Bi,Pb)-2223 core in Ag-sheathed tape

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Rare Metals 2006年第z1期25卷 400-404页

作者： LI Jingyong LI Jianguo ZHENG Huiling LI Chengshan LU Yafeng ZHOU Lian Advanced Welding Technology Provincial Key Laboratory Jiangsu University of Science and Technology Zhenjiang 212003 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Advanced Welding Technology Provincial Key Laboratory Jiangsu University of Science and Technology Zhenjiang 212003 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China Northwest Institute for Nonferrous Metal Research Xi''an 710016 China

The reformation of (Bi,Pb)-2223 from the liquid or melt is very important for a melting process of (Bi,Pb)-2223 tape. By combination of quenching experiment with X-ray diffraction (XRD) analysis, the effect of cooling rate on the evolution of three superconducting phases in the (Bi,Pb)-2223 core of Ag-sheathed tape was investigated. The results show that (Bi,Pb)-2223 reformation from the melt seems to experience different routes during slowly cooling at different rates. One is that (Bi,Pb)-2223 phase reformed directly from the melt, and no Bi-2212 participate in this process. The other is that (Bi,Pb)-2223 is converted from the intermediate product, Bi-2212, which formed from the melt during the first cooling stage. Due to the inherent sluggish formation kinetics of (Bi,Pb)-2223 from Bi-2212, only partial (Bi,Pb)-2223 can finally be reformed with the second route.

关键词： (Bi,Pb)-2223/Ag tape cooling rate decomposition and reformation

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Synthesis and Structural Characterization of Two Lead（Ⅱ） Complexes of Bis（3,5-dimethylpyrazolyl）methane

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Chinese Journal of Chemistry 2006年第6期24卷 811-816页

作者：李巧云张文华李红喜任志刚张勇郎建平 Key Laboratory of Organic Synthesis of Jiangsu Province School of Chemistry and Chemical EngineeringSuzhou University Suzhou Jiangsu 215123 China Jiangsu Laboratory of Advanced Functional Materials Changshu Institute of TechnologyChangshu Jiangsu 215500 China

Reactions of lead（Ⅱ） nitrate or perchlorate with bis（3,5-dimethylpyrazolyl）methane （dmpzm）, produced two new Pb（Ⅱ） chelated complexes [Pb（dmpzm）2X2] （X=NO3^- 1, ClO4^- 2）. Both compounds were structurally characterized by elemental analysis, IR spectroscopy, thermal analysis, and single crystal X-ray diffraction. Both compounds are mononuclear with a distorted square antiprismatic PbN4O4 coordination geometry incorporating a pair of O,O＇-bidentate anions and N,N＇-bidentate dmpzm ligands. In the crystals of 1 or 2, the methyl or methylene groups of dmpzm ligand interact with the oxygen atoms of nitrates or perchlorates to afford intra- and intermolecular hydrogen bonding, thereby forming a two-dimensional network 1 or a three-dimensional structure 2.

关键词： lead（Ⅱ） compound synthesis crystal structure bis（3,5-dimethylpyrazolyl）methane

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Synthesis of well-defined carbazole group labelled polymer via RAFT polymerization and study on the optical properties

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E-Polymers 2006年 1-12页

作者： Zhou, Di Zhu, Xiulin Zhu, Jian Hu, Lihua Cheng, Zhenping School of Chemistry and Chemical Engineering Suzhou University Suzhou 215006 China Jiangsu Key Laboratory of Advanced Functional Materials Changshu Institute of Technology Changshu 215500 China

Benzyl 9H-carbazoIe-9-carbodithioate (BCC) was synthesized and characterized. The single-crystal structure of BCC was first reported. The RAFT polymerizations of styrene and acrylates using BCC as the RAFT agent under conventional polymerization conditions were investigated. The results showed that the BCC was an effective RAFT agent for the polymerizations of styrene and acrylates. The well-controlled polymers were labelled with carbazole group, which was confirmed by 1H NMR and the chain extension of the obtained polymer. Azo modified poly(methyl acrylate) (PMA) was synthesized through a post-polymerization azo-coupling scheme. The optical properties of obtained polymer were also characterized. The results showed that the carbazole group labelled polymer exhibited fluorescence and the azo polymer exhibited UV absorption behaviour in N,N-dimethyl formamide (DMF).

关键词： Aromatic polymers

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Shell structures of sodium nanowires from atomistic simulations

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Physical Review B 2006年第20期74卷 205420-205420页

作者： Jianming Jia Daning Shi Baolin Wang Jijun Zhao Department of Physics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials and Department of Physics Huaiyin Teachers College Jiangsu 223001 China Department of Physics Nanjing University Nanjing 210093 China Department of Physics Huaiyin Institute of Technology Jiangsu 223001 China State Key Laboratory of Materials Modification by Laser Electron and Ion Beams and College of Advanced Science and Technology Dalian University of Technology Dalian 116024 China

The structural and transport properties of sodium nanowires up to 2.4nm in diameter are studied using an unbiased genetic algorithm search combined with local optimizations at the level of density-functional theory. Two competing structural series, i.e., crystalline and helical, are obtained. Helical structures are energetically more favorable for thinner wires and crystalline structures become dominant as the diameter become larger. With increasing radius, two alternative formation mechanisms of nanowires, i.e., wall-by-wall and facet based are observed. The quantum conductance of these nanowires is computed and a crossover from electronic shell to atomic shell is suggested.

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Growth behavior and magnetic properties of SinFe (n=2–14) clusters

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Physical Review B 2006年第12期73卷 125439-125439页

作者： Li Ma Jijun Zhao Jianguang Wang Baolin Wang Qiliang Lu Guanghou Wang National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Nanjing 210093 China State Key Laboratory of Materials Modification by Laser Electron and Ion Beams and College of Advanced Science and Technology Dalian University of Technology Dalian 116024 China Institute for Shock Physics Washington State University Washington 99164 USA Department of Physics Huaiyin Institute of Technology Jiangsu 223001 China

The growth behavior and magnetic properties of SinFe(n=2–14) clusters have been investigated using the density functional theory (DFT) within the generalized gradient approximation (GGA). Extensive search of the lowest-energy structures has been conducted by considering a number of structural isomers for each cluster size. In the ground state structures of SinFe clusters, the equilibrium site of Fe atom gradually moves from convex, to a surface, and to a concave site as the number of Si atoms increases from 2 to 14. Starting from n=10, the Fe atom completely falls into the center of the Si outer frame, forming metal-encapsulated Si cages. Maximum peaks were observed for SinFe clusters at n=5, 7, 10, 12 on the size-dependence of second-order energy difference, implying that these clusters possess relatively higher stability. The electronic structures and magnetic properties of SinFe clusters were discussed. We find that the magnetic moment of the Fe atom in SinFe clusters is quenched around the size of n=9–10, due to strong hybridization between the 4s and 3d states of Fe and the 3s and 3p states of Si.

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ZVS of arc welding inverter in light load

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China Welding 2005年第2期14卷 117-120页

作者：方臣富殷树言侯润石于明温永平 College of Mechanical Engineering & Applied Electronics Technology Beijing University of Technology Beijing 100022 Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang 212003

It is very difficult for arc welding inverter to realize Zero-Voltage-Switching （ZVS） because the load of arc welding inverter changes violently. An improved PS-FB-ZVS-PWM （ Phase-Shifted Full-Bridge Zero-Voltage-Switching Pulse-Width-Modulation） topology is proposed in this paper. A saturate resonant inductor is in series with the primary side of the transformer, while an auxiliary inductor is in parallel with the secondary side of the transformer to increase reactive current in light load or unload state, so the zero voltage switching of power devices is realized during switching course in light load or unload state.

关键词： soft switching arc welding inverter inductor

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Effect of welding parameters on molten pool of TIG helium-arc small-gap butt welding of tantalum sheet

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Hanjie Xuebao/Transactions of the China Welding Institution 2005年第12期26卷 43-46页

作者： Zhou, Fang-Ming Qian, Yi-Yu Jiang, Ze-Dong Shi, Yi-Feng State Key Laboratory of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China School of Material Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

In order to exploring the method to control the welding quality of thin-wall welding tube of tantalum during the production, the experimentation of TIG helium-arc small gap spot-butt welding of tantalum sheet and corresponding numerical simulation were studied. The dynamic size of molten was successfully measured with the high-speed vidicon of Fastcam 10 Kc. The numerical simulation adopted ANSYS and three-dimensional conducting-heat model in welding was set up. The effect of butting gap and clamp were synthetically considered, the result of calculation and that of the experimentation were identical better. The influence of the welding parameters on molten pool were studied by numerical simulation. The results showed the gap enhances the molten pool being elliptic. The appearing time and grow-up speed of molten pool and critical current from the calculation has the important instructional significance for optimizing the welding parameter.

关键词： Butt welding

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Topological dependence of mechanical responses of solidification microstructures in aluminum brazed joints

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中国有色金属学会会刊：英文版 2003年第6期13卷 1296-1300页

作者：高峰钱乙余 D.P.Sekulic 马鑫 F.Yoshida State Key Laboratory of Advanced Production Technology Center for Robotics and Manufacturing Systems Department of Mechanical System Engineering

The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad, and to confirm a sufficient sensitivity of a nano-indentation—load curve method for identifying the dependence. Topological features of a network of solidification microstructures(α phase and eutectic), formed during quench in a brazing process of aluminum alloy, influence significantly dynamic mechanical responses of resulting heterogeneous material. Nano/micro indentation depth vs load characteristics of differing phases suggest a spatially sensitive mechanical response of a re-solidified fillet in the joint zone. Hence, a spatial distribution, pattern formations and other morphological characteristics of microstructures have a direct impact on an ultimate joint integrity. Topology-induced variations of indentation—load curves was presented. A hypothesis involving microstructures’ spatial distribution vs mechanical response was formulated.

关键词：铝铜焊显微结构凝固拓扑相关机械响应焊接铝合金

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