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2006 8th Electronics Packaging Technology Conference, EPTC

作者： Xu, Luhua Pang, John H. L. Ren, Fei Zhang, Xi Nah, Jae-Woong Tu, K.N. School of Mechanical and Aerospace Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore Dept. of Materials Science and Engineering UCLA Los Angeles CA 90095 United States

ISBN: (纸本)142440665X

The effect of electromigration on the strain and mechanical properties change in SAC solder joint is reported. In-situ digital image speckle correlation technology was used to study the strain evolution at the lead-free solder joints during electromigration. The tensile test structure of a solder ball connected by two Cu wires of 300um diameters was prepared and tested. It is found that, during electromigration, with the atoms moving from the cathode to the anode, a tensile strain was created at the cathode region;while a compressive strain was observed at the anode region. And the strain difference between the cathode and anode kept increasing with the time of electromigration. The mechanical property of Pb-free solder joints with and without electromigration is studied by the nano-indentation continuous stiffness measurement (CSM) technology. At 100C, the applied current density was from 0 A/cm2 to 5103 A/cm2 and the time from 3 to 144 hrs. An array of 500 nm indentations was created by the nanoindenter from the cathode area, across the bulk of the solder, to the anode area. The change of Young's modulus and the hardness at the cathode and the anode was calculated from the CSM nano-indentation test. The results show that, the Young's modulus and the hardness of the anode were higher than the original values. It increases with increasing electromigration time or higher current density. On the other hand, the Young's modulus and hardness at the cathode were lower than the original values and they decrease with increasing electromigration time or higher current density. Therefore, there is a change of mechanical properties at the cathode and the anode region of the lead-free SAC solder joints due to electromigration. © 2006 IEEE.

关键词： Anodes

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Development of type II residual strains in Inconel 690 steam generator materials

Development of type II residual strains in Inconel 690 steam...

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27th Annual Conference of the Canadian Nuclear Society and 30th Canadian Nuclear Society - Nuclear Energy A World of Service to Humanity

作者： Durance, D.A. Holt, R.A. Oliver, E.C. Rogge, R. Dept. of Mechanical and Materials Engineering Queen's University Kingston Ont. Canada ISIS Rutherford Appleton Laboratory Didcot Chilton United Kingdom Neutron Program for Materials Science National Research Council of Canada Chalk River Ont. Canada

ISBN: (纸本)0919784860

The development of lattice strains as a function of applied compressive loads was evaluated employing TOF (time of flight) neutron diffraction techniques. Tests were carried out with the compression axis directed at each of the principal directions of an Inconel 690 thick-walled tube specimen. Strain measurements were carried out following sequential in-situ loading and unloading of the specimen with the scattering vector directed both parallel and perpendicular to the compression axis. The strong anisotropic elastic and plastic response observed gave rise to intergranular constraints within the material. This is verified by the crystallographic dependence on the sign and the magnitude of the residual strains measured for several different reflections.

关键词： Steam generators

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Microcellular ceramics fabricated through continuous extrusion processing

Microcellular ceramics fabricated through continuous extrusi...

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21st Technical Conference of the American Society for Composites 2006

作者： Wang, C. Wang, J. Park, C.B. Kim, Y.-W. Microcellular Plastics Manufacturing Lab. Dept. of Mechanical and Industrial Engineering University of Toronto Toronto ON M5S 3G8 Canada Dept. of Materials Science and Engineering University of Seoul Seoul 130-743 Korea Republic of

ISBN: (纸本)9781604237665

A novel extrusion processing route for fabricating microcellular ceramics with controllable open-cell content has been developed. The proposed strategy for producing microcellular ceramics involves: (i) compounding the preceramic polymer resin with quantitative expandable microspheres, combustible thermoplastics and other additives to create a ceramic precursor mixture by using a plastic compounding element, such as a twin-screw extruder;(ii) shaping and foaming the obtained ceramic-precursor using the extruder or an injection-molding machine under a temperature higher than the expanding temperature of the microspheres;and (iii) cross-linking and pyrolyzing the foamed green body at an elevated temperature to bring the organic-to-inorganic conversion to completion. At this final stage, the preceramics will be transformed into ceramics, and the fugitive expanded microspheres and thermoplastic domains will be removed. By controlling the type and amount of the expandable microspheres as well as the foaming and pyrolyzing parameters, the cell size and porosity of the obtained microcellular can be varied. Furthermore, with the deliberate control of the content of the combustible thermoplastics and the pyrolysis atmosphere, the open-cell content of produced microcellular ceramics can be adjusted. In this paper, the technique to get a desired microcellular ceramic is demonstrated and the microstructure of the produced microcellular ceramics is characterized.

关键词： Injection molding

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Californian households' willingness to pay for green PCs

Californian households' willingness to pay for green PCs

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2006 IEEE International Symposium on Electronics and the Environment

作者： Nixon, Hilary Saphores, Jean-Daniel M. Ogunseitan, Oladele A. Lincoln, John D. Shapiro, Andrew A. Irvine CA United States Program in Industrial Ecology Dept. of Environmental Health Science and Policy UCI Dept. of Chemical Engineering and Materials Science UCI Jet Propulsion Laboratory California Institute of Technology Pasadena CA United States

ISBN: (纸本)1424403510

Consumer electronic devices (CEDs) contain toxic materials including heavy metals and brominated flame retardants that can pose a threat to public and environmental health if improperly disposed Recent legislation enacted in the European Union and introduced in California bans the sale of CEDs containing these toxics. As a result, manufacturers need to change the design of their products to reduce the environmental impact, yet little is known about consumer willingness to pay for these "green" products. We estimate willingness to pay higher prices for environmentally friendly desktop computers by California households and find that most are willing to pay only 1% higher retail prices for "green" PCs. Other key demographic characteristics include age, income, and education. Environmental attitudes and beliefs are also important. © 2006 IEEE.

关键词： Personal computers

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Modeling vartm processes with equivalent porosity and permeability

Modeling vartm processes with equivalent porosity and permea...

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SAMPE '06: Creating New Opportunities For The World Economy

作者： Yoon, Myung-Keun Heider, Dirk Gillespie Jr., John W. Mechanical Engineering Department South Dakota School of Mines Rapid City SD 57701 United States Center for Composite Materials University of Delaware Newark DE 19716 United States Dept. of Materials Science and Engineering University of Delaware Newark DE 19716 United States Dept. of Civil and Environmental Engineering University of Delaware Newark DE 19716 United States Dept. of Electrical and Computer Engineering University of Delaware Newark DE 19716 United States

Numerical methods have been widely used to simulate VARTM processes to obtain optimum process parameters. Many VARTM parts have very large inplane dimensions compared to the thickness. However, the incorporation of a highly permeable distribution media on the surface of a fibrous preform results in significant through thickness flow particularily at the flow front where large gradients can exist. In general, flow simulations that can model the distribution media as a discrete layer are needed. The present study introduces a homogenous preform system using equivalent porosity and permeability in the out-of-plane direction that retains the through-thickness flow characteristics. The approach reduces the number of dimensions that needs to be modeled (e.g. 3-D is reduced to 2-D inplane and 2-D cross section is reduced to a 1-D flow problem). In this paper, 2-D flow within the cross section is considered to illustrate the technique. In this case, 2-D flow behavior is reconstructed using the 1-D solution using effective properties and an analytic solution of the flow front shape in the out-of-plane direction. The flow front locations and the through-thickness flow front profiles are compared with numerical results for a few flow scenarios to validate the present method and quantify error levels in terms of the resin fill time. Parametric studies have been carried out over a reasonable range of the input parameters such as preform thickness, porosity, and permeability. This approach significantly reduces complexity in modeling complex geometries as well as computational costs.

关键词： Resin transfer molding

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Influence of passes during ECAP on spheroidization of cementite in pearlitic steel

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Cailiao Kexue yu Gongyi/Material science and Technology 2006年第1期14卷 25-27+56页

作者： Wang, Li-Zhong Wang, Jing-Tao Huang, Jun-Xia Guo, Cheng Chen, Jin-De School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China Dept. of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China

The spheroidization behavior of cementite in pearlitic steel during equal channel angular pressing (ECAP) hot deformation at 650°C was studied, and the results show that the lamellae cementite evolved to be congeries of fine cementite particles after the first pass;spherical particles of cementite was formed after the 2nd pass;ultrafine spherical cementite particles distributed uniformly in the ultrafine grained ferrite matrix after the 5th pass of ECAP.

关键词： Steel

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Biological and biomechanical properties of chemically modified SLA titanium implants in vitro and in vivo

Biological and biomechanical properties of chemically modifi...

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作者： Feng, Yanbo Yan, Weiqi Yang, Disheng Feng, Jie Wang, Xiaoxiang Zhang, Sam Center for Bone and Joint Research Second Affiliated Hospital Zhejiang University Hangzhou China Dept. of Materials Science and Engineering Zhejiang University Hangzhou China School of Mechanical and Production Engineering Nanyang Technological University Singapore Singapore

The objective of this study was to evaluate the interface shear strength and the responses of osteoblast-like cells to titanium implants with a sandblasted and acid-etched surface modified by alkali and heat treatments (SLA-AH). The implants with machined and SLA surface served as controls. Each type of implant was characterized by scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis. In vitro assays were made using human osteoblast-like cell culture on different surfaces. The rectangle plates were also transcortically implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 4, 8 and 12 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. By SEM examination, SLA surface combined with AH treatments revealed a macro-rough surface with finely microporous structure. The in vitro assays showed that the SLA-AH surfaces exhibited more extensive cell deposition and improved cell proliferation as compared with controls. Pull-out test demonstrated that the SLA-AH treated implants had a higher mechanical strength than the controls at all interval time after implantation. Histologically, the test implants revealed a significantly greater percentage of bone-implant contact when compared with controls. The results of this study suggest that a useful approach by combined processes could optimize implant surfaces for bone deposition and produce distinct biological surface features.

关键词： Titanium

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Deformation and failure processes operating in ultra-fine grain metals 16

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16th European Conference of Fracture

作者： Hattar, K. Robertson, I.M. Han, J. Saif, T. Hearne, S.J. Follstaedt, D. Dept. of Materials Science and Engineering University of Illinois UrbanaIL61801 United States Dept of Mechanical and Industrial Engineering University of Illinois UrbanaIL61801 United States Sandia National Laboratory PO Box 5800 AlbuquerqueNM87185 United States

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Offshore technology: Introduction

Proceedings of the International Conference on Offshore Mech...

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Proceedings of the International Conference on Offshore Mechanics and Arctic engineering - OMAE 2007年 1卷 1-2页

作者： Chakrabarti, Subrata Bernitsas, Michael M. Boote, Dario Brekke, James N. Chatjigeorgiou, Ioannis K. Chitrapu, Murthy Ertekin, R.C. Falzarano, Jeffrey M. Fernandes, Antonio C. Huang, Shan Kinoshita, T. Larsen, Carl Martin Leira, Bernt Mavrakos, Spyros A. Mekha, Basim B. Morrison, Denby Grey Moros, Thanos Myrhaug, Dag Niedzwecki, John M. Pesce, Celso Pupo Riggs, Ronald Ryu, Sam Schellin, Thomas E. Schofield, Paul J. Skourup, Jesper Song, Ruxin Suzuki, Hideyuki Teigen, Per Thiagarajan, Krish P. Zimmermann, Charles-Alexandre Dept of Naval Arch and Marine Eng. University of Michigan 2600 Draper Road Ann Arbor MI 48109-2145 United States Dipartimento di Ingegneria Navale e Tecnologie Marine University of Genoa Via Montallegro no.1 16145 Genova Italy Global Marine Development Corp. 777 N. Eldridge Parkway Houston TX 77079-4493 United States P.O. Box 4379 Houston TX 77210-4379 United States Offshore Structure Analysis Inc. 13613 Capista Drive Plainfield IL 60544-7966 United States National Technical University of Athens School of Naval Architecture and Marine Engineering Zografos Campus 9 Heroon Polytechniou Ave. GR15773 Athens Greece CSC/Advanced Marine Center 1201 M Street SE Washington DC 20003 United States Dept. of Ocean and Resources Engineering Univ. of Hawaii at Manoa Holmes Hall 402 2540 Dole St. Honolulu HI 96822 United States University of New Orleans School of Naval Architecture and Marine Engineering New Orleans LA 70148 United States COPPE/UFRJ Ocean Engineering Dept. Cidade Universitaria Centro de Tecnologia Bloco C - Caixa Postal 68508 21945-970 - Rio de Janeiro - RJ Brazil Department of Naval Architecture and Ocean Engineering University of Glasgow Glasgow G12 8QQ United Kingdom Institute of Industrial Science University of Tokyo 7-22-1 Roppongi Minato-Ku Tokyo 106 Japan 7491 Trondheim Norway 7491 Trondheim Norway School of Naval Architecture and Marine Engineering National Technical University of Athens 9 Heroon Polytechniou Ave. GR-157 73 Zografou Athens Hellas Greece INTEC Engineering Partnership Ltd. 15600 JFK Boulevard Houston TX 77032 United States Shell EP Projects Shell Woodcreek 200 N. Dairy Ashford Houston TX 77001-0576 United States BP Exploration Deep Water Projects 501 Westlake Park Blvd. Houston TX 77079 United States NTNU Marin Hydrodynamikk N-7034 Trondheim-NTH Norway 301 Wisenbaker Engineering Research Center Engineering Program Office Texas A and M University College Station TX 77843-3126 United States Department of

No abstract available

ISBN: (纸本)0791842673

No abstract available

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Effect of structural parameters of wood lattice model on local buckling modes and anisotropic deformation characteristics

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Journal of the Chinese Society of mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao 2006年第2期27卷 289-292页

作者： Yamaguchi, K. Motomura, Y. Takahashi, Y. Marumo, Y. Shiozaki, H. Kawase, T. Dept. of Mechanical Engineering and Materials Science Kumamoto University 2-39-1 Kurokami Kumamoto Japan Dept. of Mechanical Engineering Sojo University 4-22-1 Ikeda Kumamoto Japan

The effects of the shape and specific gravity of the cell structures on the anisotropic deformation resistance was investigated. The analysis was carried out by parameterizing the characteristics of the cell structure using rigid-plastic finite element method. The results indicate that relative load increases as specific density (ρ) and the ratio of the lateral length (L2) to the longitudinal length (L1) in a cell increase. When L2/L1 is changed and the thickness of cell wall is held constant, relative load does not increase. Similarly, when L2/L1 is changed while ρ is held constant at a value greater than 0.50, relative load increases with increasing reduction. When ρ is less than 0.50, relative load remains almost constant as reduction increases.

关键词： Deformation characteristics Finite element method Lattice model Wood

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