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4th International Symposium on Chemical engineering and Material Properties, ISCEMP 2014

作者： Fang, Jun Lu, Shi Qiang Wang, Ke Lu Yao, Zheng Jun Jiangxi Key Laboratory of Surface Engineering Jiangxi Science and Technology Normal University Nanchang 330013 China School of Aeronautical Manufacturing Engineeringxs Nanchang Hangkong University Nanchang 330063 China Institute of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 211106 China

ISBN: (纸本)9783038352303

Based on the nonlinear FE platform ABAQUS, an elastic plastic 3D-FE model of 0Cr21Ni6Mn9N stainless steel tube was established to simulate the whole process, and its reliability was validated by experiment. Using the model, the effect of bending speed on forming quality was studied and the influence laws of bending speed on wrinkling wave ratio, wall thinning, cross section deformation and springback angle were revealed. The results show that the wrinkling wave ratio and springback angle decrease with the increasing of bending speed, while the effect of bending speed on wall thinning and cross section deformation are not significant. The maximum cross section deformation degree presents in the vicinity of the bending angle 30° along the bending direction and its position is almost unchanged with the variation of bending speed. © (2014) Trans Tech Publications, Switzerland.

关键词： Speed

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Bulging of 1420 Al-Li alloy based on Pulse Current

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Procedia engineering 2014年 81卷 808-812页

作者： Qi Xiong Xiao-tao Han Quan-liang Cao Zhi-peng Lai Qi Chen Tao Niu Zhong-yu Zhou Hong-liang Hou Liang Li Wuhan National High Magnetic Field Center HuaZhong University of Science and Technology WuHan Hubei Province 430074 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology HuaZhong University of Science and Technology WuHan Hubei Province 430074 China AVIC Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024 China

The pulse current auxiliary forming technology has been widely applied for the fabrication of complex sheet metal parts. However, the potential of high-density pulse current to generate high electromagnetic forces, which can be taken as drive forces in forming process, hasn’t been paid enough attention. Compared with the traditional gas bulging technology, bulging based on pulse current has two main advantages. One is that metal sheets can be formed directly by electromagnetic forces instead of the air pressure, and thus the airtightness of die is not an issue. The other is that the forming performance can be improved by the electro plastic effect induced by pulse currents during deformation. In this paper, to validate the effectiveness of this novel method, a special electromagnetic system for bulging of 1420 Al-Li Alloy has been designed and fabricated, in which a high-density pulse current flows through two parallel 1420 Al-Li Alloy sheets in opposite directions to generate repulsive forces for bulging. Finally, both the numerical and experimental studies are carried out to study the forming behaviour of sheets.

关键词： Electroplastic Bulging Pulse current

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Unstable spin-ice order in the stuffed metallic pyrochlore Pr2+xIr2−xO7−δ

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Physical Review B 2015年第5期92卷 054432-054432页

作者： D. E. MacLaughlin O. O. Bernal Lei Shu Jun Ishikawa Yosuke Matsumoto J.-J. Wen M. Mourigal C. Stock G. Ehlers C. L. Broholm Yo Machida Kenta Kimura Satoru Nakatsuji Yasuyuki Shimura Toshiro Sakakibara Department of Physics & Astronomy University of California Riverside California 92521 USA Institute for Solid State Physics University of Tokyo Kashiwanoha 5-1-5 Kashiwa Chiba 277-8581 Japan Department of Physics & Astronomy California State University Los Angeles California 90032 USA State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai 200433 China Collaborative Innovation Center of Advanced Microstructures Fudan University Shanghai 200433 China Institute for Quantum Matter and Department of Physics and Astronomy The Johns Hopkins University Baltimore Maryland 21218 USA NIST Center for Neutron Research National Institute of Standards and Technology Gaithersburg Maryland 20899 USA Quantum Condensed Matter Division Neutron Sciences Directorate Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Materials Science and Engineering The Johns Hopkins University Baltimore Maryland 21218 USA PRESTO Japan Science and Technology Agency (JST) 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan

Specific heat, elastic neutron scattering, and muon spin rotation (μSR) experiments have been carried out on a well-characterized sample of “stuffed” (Pr-rich) Pr2+xIr2−xO7−δ. Elastic neutron scattering shows the onset of long-range spin-ice “2-in/2-out” magnetic order at TM=0.93 K, with an ordered moment of 1.7(1)μB/Pr ion at low temperatures. Approximate lower bounds on the correlation length and correlation time in the ordered state are 170 Å and 0.7 ns, respectively. μSR experiments yield an upper bound 2.6(7) mT on the local field Bloc4f at the muon site, which is nearly two orders of magnitude smaller than the expected dipolar field for long-range spin-ice ordering of 1.7μB moments (120–270 mT, depending on muon site). This shortfall is due in part to splitting of the non-Kramers crystal-field ground-state doublets of near-neighbor Pr3+ ions by the μ+-induced lattice distortion. For this to be the only effect, however, ∼160 Pr moments out to a distance of ∼14 Å must be suppressed. An alternative scenario, which is consistent with the observed reduced nuclear hyperfine Schottky anomaly in the specific heat, invokes slow correlated Pr-moment fluctuations in the ordered state that average Bloc4f on the μSR time scale (∼10−7s), but are static on the time scale of the elastic neutron scattering experiments (∼10−9s). In this picture, the dynamic muon relaxation suggests a Pr3+4f correlation time of a few nanoseconds, which should be observable in a neutron spin echo experiment.

关键词： SPIN waves PYROCHLORE PRASEODYMIUM INELASTIC neutron scattering MUON spin rotation CRYSTAL field theory GROUND state (Quantum mechanics)

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Synthesis and characterization of zinc oxide hollow and flower likemicrospheres by simple one step solvothermal approach

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2013 3rd International Conference on key engineering Materials, ICKEM 2013

作者： Jamil, Saba Jing, Xiao Yan Jun, Wang Zhang, Mi Lin Key Laboratory of Superlight Material and Surface Technology Ministry of Education Harbin Engineering University 150001 China Institute of Advanced Marine Materials Harbin Engineering University 150001 China

ISBN: (纸本)9783037857045

Zinc oxide with spherical shaped and flower shaped morphology are prepared by simple one step solvothermal method. The product is subjected to characterization to investigate the morphology and size by using X ray diffraction, semi electron microscopy and transmission electron microscopy. The size of the prepared zinc oxide particle is in the range of 1 micrometer to 3 micrometers. The outer surface of the particles is not smooth but it is rough. The possible formation mechanism for the product is investigated that is further justified by means of structural characterization. © (2013) Trans Tech Publications, Switzerland.

关键词： Morphology

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Electrical and mechanical performance of graphene sheets exposed to oxidative environments

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Nano Research 2013年第7期6卷 485-495页

作者： Mario Lanza Yan Wang Teng Gao Albin Bayerl Marc Porti Montserrat Nafria Yangbo Zhou Guangyin Jing Yanfeng Zhang Zhongfan Liu Dapeng Yu Huiling Duan State Key Laboratory for Turbulence and Complex System Department of Mechanics and Aerospace Engineering CAPT College of Engineering Peking University Beijing 100871 China Beijing Aeronautical Science and Technology Research Institute Beijing 10221 I China Center for Nanochemistry (CNC) Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Unstable and Stable Species College of Chemistry and Molecular Engineering Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China Electronic Engineering Department Universitat Autonoma de Barcelona Cerdanyola del Valles 08193 Spain Department of Physics State Key Laboratory for Mesoscopic Physics Peking University Beijing 100871 China Physics Department Northwest University Xi'an 710069 China

Graphene coatings have been shown to protect the underlying material from oxidation when exposed to different media. However, the passivating properties of graphene in air at room temperature, which corresponds to the operating conditions of many electronic devices, still remain undear. In this work, we analyze the oxidation kinetics of graphene/Cu samples in air at room temperature for long periods of time （from I day to 113 days） using scanning electron microscopy, conductive atomic force microscopy and Auger electron microscop3~ and we compare the results with those obtained for similar samples treated in H202. We observe that unlike the graphene sheets exposed to H202, in which the accumulation of oxygen at the graphene domain boundaries evolves in a very controlled and progressive way, the local oxidation of graphene in air happens in a disordered manner. In both cases the oxide hillocks formed at the graphene domain boundaries can propagate to the domains until reaching a limiting width and height. Our results demonstrate that the local oxidation of the underlying material along the domain boundaries can dramatically decrease the roughness, conductivity, mechanical resistance and frictional characteristics of the graphene sheet, which reduces the performance of the whole device.

关键词： graphene local oxidation domain boundary passivating layer

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Simulation and experiments on plasticity and recrystallisation in SX superalloys by investment casting

Simulation and experiments on plasticity and recrystallisati...

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12th IUMRS International Conference on advanced Materials(IUMRS-ICAM2013)

作者： Z.Li Q.Xu J.Xiong J.Li B.Liu School of Materials Science and Engineering Key Laboratory for Advanced Materials Processing TechnologyMinistry of EducationTsinghua University National Key Laboratory of Science and Technology on Advanced High Temperature Structural Materials Beijing Institute of Aeronautical Materials

Modelling and targeted experimentation on the rod casting with ceramic core were used to quantify the plasticity, recrystallisation during the subsequent solution heat treatment, as a result of the different thermal contractions of the metal, ceramic shell and core during directional solidification. Thermal–elastic–plastic analysis was carried out with the high temperature plasticity assumed to be the rate independent, considering the orthotropic characteristics of single crystal nickel base superalloys. The calculation results indicate that the plasticity occurs mainly during two stages: the initial solidification stages(around solidus) owing to its low immediate yield strength, and the later solidification stage(below 800°C) due to the thermal contraction. The influential factors, such as wall and shell thickness, flanges, etc., are analysed. Experimentally,recrystallisation takes place in the thin walled areas due to broken or buckled cores, which agrees well with the plasticity calculations.

关键词： Recrystallisation,Directional solidification,Single crystal,Superalloys

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Spin-Hall conductivity and electric polarization in metallic thin films

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Physical Review B 2013年第8期87卷 081407(R)-081407(R)页

作者： Xuhui Wang Jiang Xiao (萧江) Aurelien Manchon Sadamichi Maekawa King Abdullah University of Science and Technology (KAUST) Physical Science and Engineering Division Thuwal 23955-6900 Saudi Arabia Department of Physics and State Key Laboratory of Surface Physics Fudan University Shanghai 200433 China Center for Spintronic Devices and Applications Fudan University Shanghai 200433 China Advanced Science Research Center Japan Atomic Energy Agency Tokai 319-1195 Japan CREST Japan Science and Technology Agency Tokyo 102-0075 Japan

We predict theoretically that when a normal metallic thin film (without bulk spin-orbit coupling, such as Cu or Al) is sandwiched by two insulators, two prominent effects arise due to the interfacial spin-orbit coupling: a giant spin-Hall conductivity due to the surface scattering and a transverse electric polarization due to the spin-dependent phase shift in the spinor wave functions.

关键词： METALLIC thin films SPIN Hall effect POLARIZATION (Electricity) -- Frequency effects SPIN-orbit coupling PHASE shift (Nuclear physics)

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Synthesis, properties, and mechanism of two novel photoisomerization pyrazolones in the solid state

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Journal of Molecular Structure 2013年 1035卷 271-276页

作者： Mingxi Guo Jixi Guo Dianzeng Jia Hu Liu Lang Liu Anjie Liu Feng Li Key Laboratory of Material and Technology for Clean Energy Ministry of Education Key Laboratory of Advanced Functional Materials Autonomous Region Institute of Applied Chemistry Xinjiang University Urumqi 830046 Xinjiang PR China State Laboratory of Surface and Interface Science and Technology School of Materials and Chemical Engineering Zhengzhou University of Light Industry Zhengzhou 450002 Henan PR China University of Texas M.D. Anderson Cancer Center Houston TX 77002 USA

Two novel photoisomerization compounds derived from pyrazolones have been synthesized successfully. The photoisomerization properties of materials have been carefully investigated by measuring the UV–vis absorption and fluorescence spectra of the materials. It was found for the first time among the derivatives of pyrazolones that the compounds change their color from yellow to brown with an efficiency of more than 95% of modulating the fluorescence behaviors, after irradiated with visible light. The unique fluorescent changes of the two compounds between their “on” and “off” states in the solid state indicate that the materials could be used as building blocks to construct novel optical switches. The mechanism of the photoisomerization was further studied with FT-IR, XPS and X-ray single crystal diffraction. The photoreaction resulted from isomerization between the enol and keto forms of the materials is accompanied by intra- and inter-molecular proton transfer.

关键词： Pyrazolone Photoisomerization Fluorescence modulation Optical switch Proton transfer Hydrogen bond

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Microstructures and properties of SnZn-xEr lead-free solders

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Journal of Rare Earths 2012年第8期30卷 790-793页

作者：张亮崔俊华韩继光郭永环何成文 School of Mechanical&Electrical Engineering Jiangsu Normal University Provincial Key Laboratory of Advanced Welding Jiangsu University of Science and Technology Department of Basic Experiment Naval Aeronautical and Astronautical University

The Sn9Zn eutectic alloy is the nontoxic lead-free solders alternative having a melting temperature which is closest to that of the eutectic SnPb alloy. In order to improve the properties of SnZn lead-free solders, 0-0.5 wt.% of rare earth Er was added to the base alloys, and the microstructures were studied. Results showed that the addition of rare earth Er could enhance the wettability of SnZn solders, with 0.08%Er addition, the spreading area gavc an 19.1% increase. And based on the mechanical testing, it was found that the tensile force and shear force of SnZn-xEr solder joints could be improved significantly. Moreover, the oxidation resistance of SnZn0.08Er solder was better than that of SnZn solder, in addition, it was found that trace amounts of rare earth Er could refine the microstructures of SnZn solders, espe- cially for Zn-rich phases, and excessive amount of rare earth Er led to a coarse microstructure.

关键词： lead-free solders solder joints mechanical orooerties： oxidation resistance rare earths

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High-temperature mechanical properties and deformation behavior of high Nb containing TiAl alloys fabricated by spark plasma sintering

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 354-359页

作者： Xin Lu Li-hua Zhao Lang-ping Zhu Bin Zhang Xuan-hui Qu State Key Laboratory for Advanced Metals end Materials School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Beijing Institute of Aeronautical Materials Beijing 100095 China

A high Nb containing TiA1 alloy was prepared from the pre-alloyed powder of Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y （at%） by spark plasma sintering （SPS）. Its high-temperature mechanical properties and compressive deformation behavior were investigated in a temperature range of 700 to 1050℃ and a strain rate range of 0.002 to 0.2 s 1. The results show that the high-temperature mechanical properties of the high Nb containing TiA1 alloy are sensitive to deformation temperature and strain rate, and the sensitivity to strain rate tends to rise with the deformation temperature increasing. The hot workability of the alloy is good at temperatures higher than 900℃, while fracture occurs at lower temperatures. The flow curves of the samples compressed at or above 900℃ exhibit obvious flow softening after the peak stress. Un- der the deformation condition of 900-1050℃ and 0.002-0.2 s 1, the interrelations of peak flow stress, strain rate, and deformation tempera- ture follow the Arrhenius＇ equation modified by a hyperbolic sine function with a stress exponent of 5.99 and an apparent activation energy of 441.2 ***-1.

关键词： titanium-aluminum alloys spark plasma sintering （SPS） mechanical properties deformation activation energy

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