Advanced Engineering Materials

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  1. Full Papers

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      Microstructure, Shape Memory Effect and Functional Stability of Ti67Ta33 Thin Films

      Yahya Motemani, Peter M. Kadletz, Bernd Maier, Ramona Rynko, Christoph Somsen, Alexander Paulsen, Jan Frenzel, Wolfgang W. Schmahl, Gunther Eggeler and Alfred Ludwig

      Article first published online: 27 FEB 2015 | DOI: 10.1002/adem.201400576

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      Ti–Ta thin films can be used as high-temperature micro-actuators. In this study, microstructure, shape memory effect, and functional stability of room-temperature sputter deposited Ti67Ta33 thin films are systematically investigated. The actuation response of the film actuators degrades significantly during thermal cycling. This degradation is related to the formation of nanoscale ω precipitates (5–13 nm) which form above the austenite finish temperature.

    2. Mechanical Characterization of Fiber Ceramics: Effect of Temperature**

      Matti Järveläinen, Joonas Humalamäki, Jarmo Laakso and Erkki Levänen

      Article first published online: 17 FEB 2015 | DOI: 10.1002/adem.201400512

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      Fibrous ceramic structures are used in thermal insulators and filters in high-temperature processes. Their mechanical properties are surprisingly complex, being governed by force fields transmitting in the net of fibers. Examining how the fibers link to each other sheds light to this quandary. Extent of linking is defined by the fiber free length (deep red), which is the distance between the closest contact points (green) of a fiber. Decrease of free length, as neighboring fibers (blue) develop contacts, explains why these structures turn rigid with heat. When analyzed with grit blasting, this can be used to discover the structure's thermal history.

    3. Effect of Pre-Deformation and Subsequent Aging on the Damping Capacity of Mn-20 at.%Cu-5 at.%Ni-2 at.%Fe alloy

      Yan Jiazhen, Li Ning, Fu Xu, Liu Wenbo, Liu Ying and Zhao Xiuchen

      Article first published online: 16 FEB 2015 | DOI: 10.1002/adem.201400507

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      The damping capacity of Mn-20 at.%Cu-5 at.%Ni-2 at.%Fe alloy decreases rapidly with increase in deformation degree, attributing to the rearranged martensite plates and the introduced defects which hinder the motion of the twin and phase boundaries. The damping capacity of the pre-deformed alloy can be completely or partly recovered by aging at 435 °C for 20 min.

  2. Editorials

    1. First International Conference on Laser Polishing LaP 2014

      Edgar Willenborg

      Article first published online: 16 FEB 2015 | DOI: 10.1002/adem.201400575

  3. Full Papers

    1. Thermal Stability of the Commercial Mg-PSZ Powders

      Dmytro Pavlyuchkov, Stefan Martin, Benedikt Reichel, Christian Weigelt and Olga Fabrichnaya

      Article first published online: 13 FEB 2015 | DOI: 10.1002/adem.201400521

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      Stability of the Mg-PSZ commercial powders used as reinforced ceramic components of the TRIP metal matrix composite is studied at 1350 °C. Two mechanisms of destabilization of the Mg-PSZ ceramics are proposed. Stability of the powders is mainly related to their dispersion degree.

    2. Quantitative 3D X-ray Imaging of Densification, Delamination and Fracture in a Micro-Composite under Compression

      Jostein Bø Fløystad, Eirik Torbjørn Bakken Skjønsfjell, Manuel Guizar-Sicairos, Kristin Høydalsvik, Jianying He, Jens Wenzel Andreasen, Zhiliang Zhang and Dag Werner Breiby

      Article first published online: 10 FEB 2015 | DOI: 10.1002/adem.201400443

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      Ptychographic X-ray microscopy can be used for quantitatively studying the mechanical properties of microscale composites. Phase-contrast three-dimensional tomograms reveal with unprecedented detail the mechanical response, including delamination, densification and fracture, of a polymer-core/silver-shell micro-composite subjected in situ to a mechanical compression test.

    3. In Situ Synthesis of (TiC + Ti3SiC2 + Ti5Si3)/Ti6Al4V Composites with Tailored Two-scale Architecture

      C. Liu, L. J. Huang, L. Geng, Y. Jiao and A. Tang

      Article first published online: 10 FEB 2015 | DOI: 10.1002/adem.201400585

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      Hybrid (TiC + Ti3SiC2 + Ti5Si3)/Ti6Al4V composites with a tailored two-scale architecture have been successfully fabricated by powder metallurgy technology. The equiaxial TiC and bar-like Ti3SiC2 are synthesized by in situ reaction between Ti and SiC, distributing on the network boundary, which is the first-scale architecture. The ultrafine Ti5Si3 needles precipitated in intergranular β phase after a cooling process form the secondary-scale architecture, which significantly contributes to the strength of this composite by dispersion strengthening.

  4. Communications

    1. Crack Evolution and Estimation of Fracture Toughness of HfO2/SiCN(O) Polymer Derived Ceramic Nanocomposites

      Ravindran Sujith, Andre Zimmermann and Ravi Kumar

      Article first published online: 9 FEB 2015 | DOI: 10.1002/adem.201400525

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      Radial cracks are observed upon indentation of HfO2/SiCN(O) polymer derived ceramic nanocomposites. Crack opening displacement and radial crack length measurement are used to estimate the fracture toughness. The values obtained from the two methods showed deviation indicating the presence of open network forming structures.

  5. Full Papers

    1. Hypervelocity Impact Testing of a Metallic Glass-Stuffed Whipple Shield

      Douglas C. Hofmann, Lee Hamill, Eric Christiansen and Steve Nutt

      Article first published online: 6 FEB 2015 | DOI: 10.1002/adem.201400518

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      Images from a video showing the impact of an aluminum projectile at 7 km × s−1 into a spacecraft shield comprised of layers of metallic glass and aluminum.

  6. Communications

    1. Flexible, stretchable and weavable piezoelectric fiber

      Hyeon Jun Sim, Changsoon Choi, Chang Jun Lee, Youn Tae Kim, Geoffrey M. Spinks, Marcio D. Lima, Ray H. Baughman and Seon Jeong Kim

      Article first published online: 6 FEB 2015 | DOI: 10.1002/adem.201500018

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      The flexible piezoelectric fibers can be stretched to a tensile strain of 5% and can generate over 50 μW·cm−3.The FPFs are sufficiently robust for knotting, sewing and weaving and can also be converting to piezoelectric coils by twist insertion. These spring-like coils can be reversibly stretched to 50% strain without failure.

  7. Reviews

    1. Advanced Micro-Lattice Materials

      Jian Xiong, Robert Mines, Ranajay Ghosh, Ashkan Vaziri, Li Ma, Arne Ohrndorf, Hans-Jürgen Christ and Linzhi Wu

      Article first published online: 4 FEB 2015 | DOI: 10.1002/adem.201400471

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      Topological management of materials at a Micro-scale is one of the fundamental building principles of nature. This combination of material and structural properties results in marked changes in the properties of solids. Nowadays physicists, chemists, materials scientists and engineers explore those effects by synthesizing, characterizing, and modeling Micro-lattice materials from all material classes. Applications have been identified in the fields of ultra-lightweight structures, thermal equipments, electrochemical devices, high absorption capacity and bio-repair materials. This article aims to review recent progress in the development of such advanced Micro-lattice materials.

  8. Communications

    1. X-ray Imaging and Controlled Solidification of Al-Cu Alloys Toward Microstructures by Design

      Amy J. Clarke, Damien Tourret, Seth D. Imhoff, Paul J. Gibbs, Kamel Fezzaa, Jason C. Cooley, Wah-Keat Lee, Alex Deriy, Brian M. Patterson, Pallas A. Papin, Kester D. Clarke, Robert D. Field and James L. Smith

      Article first published online: 30 JAN 2015 | DOI: 10.1002/adem.201400469

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      X-ray imaging, which permits the microscopic visualization of metal alloy solidification dynamics, can be coupled with controlled solidification to create microstructures by design. This x-ray image shows a process-derived composite microstructure being made from a eutectic Al-17.1 at.%Cu alloy by successive solidification and remelting steps.

  9. Full Papers

    1. Metallic Braided Structures: The Mechanical Modeling

      Djihad Rial, Amine Tiar, Kebir Hocine, Jean-Marc Roelandt and Eric Wintrebert

      Article first published online: 28 JAN 2015 | DOI: 10.1002/adem.201400422

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      The mechanical behavior of metallic braided structures used in the piping industry is investigated experimentally and numerically. Because such structures are not a continuum, their behavior needs a large finite element models. In order to overcome the huge computational cost, three finite element models are proposed in which two are based on homogenization.

    2. Transparent Conductive Metal Thin-Film Electrodes Structured by Direct Laser Interference Patterning

      Lars Müller-Meskamp, Sylvio Schubert, Teja Roch, Sebastian Eckhardt, Andrés-Fabián Lasagni and Karl Leo

      Article first published online: 28 JAN 2015 | DOI: 10.1002/adem.201400454

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      Using direct laser interference patterning (DLIP), we are able to structure thin metal films by direct ablation in a fast, single step process. To achieve beneficial pattern and ablation properties, different sublayers of MoOx, Au, Al, Cr or organics below the silver film and different laser power densities and pulse numbers are investigated. The resulting mesh-like, hexagonally periodic array of apertures shows improved transmittance and sheet resistance. The nanostructured thin-films have great potential to be combined with dielectric antireflection layers as transparent electrode for any thin-film optoelectronic devices.

    3. Tuning the Electromechanical Properties of Silicones by Crosslinking Agent

      Adrian Bele, Maria Cazacu, Carmen Racles, George Stiubianu, Dragos Ovezea and Mircea Ignat

      Article first published online: 23 JAN 2015 | DOI: 10.1002/adem.201400505

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      R-trialkoxysilanes, with R of different polarities, are used as crosslinking agents for polydimethylsiloxane-α,ω-diols in order to optimize the properties of interest for electromechanical actuation (strain, Young modulus, dielectric permittivity, dielectric loss) as well as other material properties.

    4. Direct Inkjet Printing of Dielectric Ceramic/Polymer Composite Thick Films

      Morten Mikolajek, Andreas Friederich, Christian Kohler, Melanie Rosen, Andreas Rathjen, Klaus Krüger and Joachim R. Binder

      Article first published online: 21 JAN 2015 | DOI: 10.1002/adem.201400451

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      A novel preparation route for composite thick films via inkjet printing is shown by development of a ceramic/polymer composite ink. This allows the fabrication of composite dielectric thick films in one process step. The drying behavior of the ink shows no coffee stain effect and homogeneous structures are obtained. All-inkjet-printed capacitors were fabricated with improved dielectric properties compared to the pure polymer.

    5. Enhanced Mechanical Properties of Microalloyed Austenitic Stainless Steel Produced by Martensite Treatment

      Mohammad Shirdel, Hamed Mirzadeh and Mohammad Habibi Parsa

      Article first published online: 20 JAN 2015 | DOI: 10.1002/adem.201400541

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      Ultrafine grained austenitic microstructure with bimodal grain size distribution and by incorporation of small amount of thermally-induced martensite was obtained in a microalloyed austenitic stainless steel through the reversion of strain-induced martensite to achieve superior mechanical properties.

    6. Oxide Formation, Morphology, and Nanohardness of Laser-Patterned Steel Surfaces

      Andreas Rosenkranz, Leander Reinert, Carsten Gachot, Hisham Aboufadl, Samuel Grandthyll, Karin Jacobs, Frank Müller and Frank Mücklich

      Article first published online: 20 JAN 2015 | DOI: 10.1002/adem.201400487

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      In this research work, stainless steel samples are laser-patterned with a line-like surface pattern. A detailed chemical analysis is performed by X-ray photoelectron spectroscopy and atom probe tomography. The chemical properties are correlated with microstructural properties such as nanohardness.

  10. Communications

    1. Self Healing of Creep Damage by Gold Precipitation in Iron Alloys

      Shasha Zhang, Cees Kwakernaak, Willem Sloof, Ekkes Brück, Sybrand van der Zwaag and Niels van Dijk

      Article first published online: 15 JAN 2015 | DOI: 10.1002/adem.201400511

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      Autonomous repair of high-temperature creep damage in iron alloys can be achieved by adding gold. Like biological systems, metals can self heal damage during operation. The selective gold precipitation at the early-stage creep cavities results in a pore filling, and thereby damage repair. This mechanism strongly enhances the creep lifetime and opens new opportunities for self healing in metals.

  11. Full Papers

    1. Capability of New High Strength ADI-Materials for Automotive Components under Crash Loading

      Wolfgang Böhme and Lutz Reissig

      Article first published online: 15 JAN 2015 | DOI: 10.1002/adem.201400435

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      High strength properties and large elongations at fracture are determined for two ADI materials by high rate tensile tests. The reason for this good crash performance might be a significant reduction of the austenite phase as detected with EBSD after the tests. This indicates a phase transformation comparable to a TRIP effect.

    2. Skins and Sleeves for Soft Robotics: Inspiration from Nature and Architecture

      Constantina Lekakou, Yahya Elsayed, Tao Geng and Chakravarthini M. Saaj

      Article first published online: 15 JAN 2015 | DOI: 10.1002/adem.201400406

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      The image shows pneumatically actuated soft robot arms with skins inspired from nature and architecture: a crimped, braided sleeve inspired from an elephant trunk, and an internal dragonskin inspired from a Dragon Pavilion design. The microstructure of such skins and sleeves makes them able to guide and follow the arm deformation, restrict ballooning and stiffen the arm upon actuation.

  12. Communications

    1. Soft Actuation of Structured Cylinders through Auxetic Behavior

      Arnaud Lazarus and Pedro M. Reis

      Article first published online: 13 JAN 2015 | DOI: 10.1002/adem.201400433

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      We introduce a new class of soft actuators based on the buckling of locally patterned elastic cylindrical shells that can be designed to reversibly achieve flexural or twisting motion. Depressurizing our samples allows for tunable and controllable motion. Given that the deformation is primarily governed by geometry and elasticity, the resulting modes of actuation should be readily scalable.

  13. Full Papers

    1. Process- and Material-Induced Surface Structures During Laser Polishing

      Christian Nüsser, Judith Kumstel, Thomas Kiedrowski, Andrei Diatlov and Edgar Willenborg

      Article first published online: 8 JAN 2015 | DOI: 10.1002/adem.201400426

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      The roughness after laser polishing does not only contain remains of the initial surface roughness, it also contains new roughness due to surface structures, which are introduced by the polishing process. Since these structures greatly contribute to the roughness, it is necessary to understand the mechanisms that lead to their formation so as to prevent the structures from forming and allow higher smoothing of the surface. Hence, in this publication it is investigated why these structures occur, what the influencing parameters are and how their influence on the roughness can be reduced, for both laser macro and laser micro polishing.

    2. The Mechanical Behavior of ALD-Polymer Hybrid Films Under Tensile Strain

      Anuradha Bulusu, Samuel Graham, Hendrik Bahre, Henrik Behm, Marc Böke, Rainer Dahlmann, Christian Hopmann and Jörg Winter

      Article first published online: 8 JAN 2015 | DOI: 10.1002/adem.201400431

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      Atomic layer deposited films on polymers on PET substrates are subjected to tensile strain. Spectroscopic characterization show varying degrees of penetration of the ALD films into the polymers. While critical tensile strain remained unchanged the softer polymer underlayers appear to help decrease saturation crack density of the brittle ALD films.

  14. Reviews

    1. Review of Recent Developments in the Field of Magnesium Corrosion

      Andrej Atrens, Guang-Ling Song, Ming Liu, Zhiming Shi, Fuyong Cao and Matthew S. Dargusch

      Article first published online: 7 JAN 2015 | DOI: 10.1002/adem.201400434

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      Invited Review. Recent developments in the field of Mg corrosion are reviewed: corrosion manifestations, material influences, surface treatment, anodisation, coatings, inhibition, biodegradable medical applications, stress corrosion cracking, flammability, corrosion mechanisms for HP Mg, and critical evaluation of corrosion mechanisms. Much research continues, and is expected to produce better Mg alloys. The graphic shows high-purity Mg after 7 days corrosion in a concentrated chloride solution. A. Atrens,* G. -L. Song, M. Liu, Z. Shi, F. Cao, and M. S. Dargusch Review of Recent Developments in the Field of Magnesium Corrosion.

  15. Full Papers

    1. Multi-Axial Incremental Forging and Shearing as a New Severe Plastic Deformation Processing Technique

      M. Montazeri-Pour, M. H. Parsa, Ali Khajezade and H. Mirzadeh

      Article first published online: 7 JAN 2015 | DOI: 10.1002/adem.201400467

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      A novel severe plastic deformation (SPD) technique called Multi-Axial Incremental Forging and Shearing (MAIFS) is introduced in this work for deforming materials to high imposed plastic strains and subsequent grain refinement. The MAIFS process consists of incremental forging (or incremental back extrusion) followed by angular pressing. Thus, it combines some of the main advantages of equal channel angular pressing (ECAP) and multi-directional forging (MDF) techniques to enhance the degree of deformation and to increase the deformation homogeneity of the workpiece after a few passes. The evaluation of this technique by characterizing the flow behavior of a tin-based alloy demonstrates that acceptable deformation homogeneity can be achieved after even passes of the process. In comparison with some SPD techniques which require complicated design or expensive facilities, MAIFS method needs no special equipment and it offers a great potential for cost-effective processing of various bulk ultrafine grained and nanostructured materials.

    2. Efficient and Simple Surface Modification of Carbon Nanotubes by Dry Process Using hydrogen

      S.Y. Moon, T. Ogasawara, S. Hanamitsu, K. Shioda and Y. Inoue

      Article first published online: 7 JAN 2015 | DOI: 10.1002/adem.201400495

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      Hydrogen treatment is a facile method to functionalize CNT surface. It changed surface properties with generating active sites on the surface without breakdown of their alignment. This method is an effective to improve interface bonding properties with other materials.

    3. Fatigue Behavior and Lifetime Prediction of Unidirectionally Wire Reinforced Lightweight Metal Matrix Composites

      Matthias Merzkirch, Thilo Hammers, Andreas Reeb, Thomas Schwind, Sascha Riedl, Leon Thiel, Alexander Henschel, Eberhard Kerscher, Volker Schulze and Kay André Weidenmann

      Article first published online: 7 JAN 2015 | DOI: 10.1002/adem.201400354

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      Monofilament reinforced MMCs show a significant increase in lifetime under fatigue loading. Based on the knowledge of the quasi-static behaviour of the single components and the fatigue behaviour of the matrix material a new model is used to predict the lifetime for different wire reinforced aluminium and magnesium alloys. The fatigue properties are compared according to the light-weight aspect.

    4. Temporal Electret Behavior of Polymer Films Exposed to Cold Radiofrequency Plasma

      Edward Bormashenko, Roman Pogreb, Gilad Chaniel, Victor Multanen and Alexander Ya. Malkin

      Article first published online: 3 JAN 2015 | DOI: 10.1002/adem.201400445

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      We report the electret response of cold plasma treated polypropylene and low-density polyethylene films, which is damping with time. The damping of electret response occurs in parallel with the hydrophobic recovery of films, resulting in the growth of the apparent contact angle. Three distinct scale times of electric and hydrophobic recoveries are recognized.

    5. Effect of Interface Evolution on Thermal Conductivity of Vacuum Hot Pressed SiC/Al Composites

      Zhizhong Chen, Zhanqiu Tan, Gang Ji, Genlian Fan, Dominique Schryvers, Qiubao Ouyang and Zhiqiang Li

      Article first published online: 2 JAN 2015 | DOI: 10.1002/adem.201400412

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      Vacuum hot pressing allows to tailor nanoscale interfacial structures, namely non-bonded, diffusion-bonded, and reaction-bonded interfaces in SiC/Al composites. The diffusion-bonded interface, a tightly-adhered interface without Al4C3, is the most favorable.

    6. Wear Behavior of Laser-Patterned Piston Rings in Squeeze Film Dampers

      Andreas Rosenkranz, Steffen Jaeger, Carsten Gachot, Sabrina Vogel and Frank Mücklich

      Article first published online: 2 JAN 2015 | DOI: 10.1002/adem.201400481

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      In this research work, the piston rings of a squeeze film damper are patterned with a dot-like structure (4 μm period and 1 μm depth) produced by three-beam interference (pulse duration of 10 ns). This analysis demonstrates an 85% reduction in the wear volume of the patterned piston rings.

    7. Micro-Forming Using Ultrafine-Grained Aluminum Processed by Equal-Channel Angular Pressing

      Jie Xu, Xiaocheng Zhu, Lei Shi, Debin Shan, Bin Guo and Terence G. Langdon

      Article first published online: 2 JAN 2015 | DOI: 10.1002/adem.201400448

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      Pure aluminum was processed by equal-channel angular pressing to produce an ultrafine-grained (UFG) microstructure and the formability was then evaluated using micro-forming technology.

    8. Fabrication of Riblet Structures on a Ni-based Superalloy (PWA1483) for Potential Drag Reduction in High Temperature Applications Based on Laser Optimization

      Antje Schlieter, I. Shakhverdova and C. Leyens

      Article first published online: 2 JAN 2015 | DOI: 10.1002/adem.201400365

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      The several micrometer sized riblets are fabricated on a thin multilayered Ni-Cr-Ni coating deposited onto a PWA1483 alloy. The innovative manufacturing method includes laser ablation of the coating and subsequent oxidation, forming mechanically stable structure.

    9. Effects of Temperature and Stress on Microstructural Evolution during Creep Deformation of Ru-free and Ru-containing Single Crystal Superalloys

      Xinguang Wang, Jinlai Liu, Tao Jin, Xiaofeng Sun, Zhuangqi Hu, Jeonghyeon Do, Baiggyu Choi, I. S. Kim and Changyong Jo

      Article first published online: 29 DEC 2014 | DOI: 10.1002/adem.201400400

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      The effects of temperature and stress on microstructural evolution are studied. Ru additions support the topological inversion; the a <101> superdislocations only present at relatively high temperature; the a <010> superdislocations are identified at all creep conditions and considered more energetically favorable than other type dislocations.

    10. Human Neuronal SHSY5Y Cells on PVDF:PTrFE Copolymer Thin Films

      Ilaria Tonazzini, Eva Bystrenova, Beatrice Chelli, Pierpaolo Greco, Dago De Leeuw and Fabio Biscarini

      Article first published online: 29 DEC 2014 | DOI: 10.1002/adem.201400441

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      We study the in vitro biocompatibility of polyvinylidenefluoride (PVDF)–polytrifluoroethylene (PTrFE) copolymer thin films using SHSY5Y human neuronal cells. The aim is to test this film as a capping layer for hybrid bio-organic electronic transducers. We show that PVDF:PTrFE thin films allowed standard SHSY5Y proliferation and neuro differentiation, even if with reduced short-term cell adhesion.

    11. Preparation of Quasi-Ternary Fe-P-C Bulk Metallic Glass Using Industrial Raw Materials with the Help of Fluxing Technique

      Haibo Ling, Qiang Li, Jijun Zhang, Yaqiang Dong, Chuntao Chang, Hongxiang Li, Jaeheon Ki and Seonghoon Yi

      Article first published online: 23 DEC 2014 | DOI: 10.1002/adem.201400399

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      Bulk quasi-ternary Fe80P13C7 glassy alloy rod with a diameter of 1–mm has been prepared by combining fluxing treatment and J-quenching technique using industrial raw materials.

    12. Machine Tool and CAM-NC Data Chain for Laser Polishing Complex Shaped Parts

      John Flemmer, Ingo Ross, Edgar Willenborg and Horst Fröba

      Article first published online: 23 DEC 2014 | DOI: 10.1002/adem.201400476

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      Its high impact on functional and aesthetical properties makes the polishing process a crucial part of the manufacturing process of tools and dies. While manual polishing still is the state of the art for a wide spectrum of finishing tasks, the laser polishing process offers the possibility for complete automation, high processing speed, high shape retention, and unique surface properties. In order to bring laser polishing from laboratory to industrial scale; or from flat test samples to complex 3D freeform surfaces such as molds or dies; several challenges have to be met.

    13. Mo–Si–B Coating for Improved Oxidation Resistance of Niobium

      Otto J. Lu-Steffes, Linfen Su, Dana M. Jackson and John H. Perepezko

      Article first published online: 23 DEC 2014 | DOI: 10.1002/adem.201400438

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      A Mo–Si–B based coating is applied to niobium producing a coating structure composing of molybdenum and niobium silicides. Upon oxidation, the coating forms an aluminosilica scale, providing oxidation protection for Nb, showing promise as a potential barrier for high temperature applications.

    14. Quantitative Assessment of the Reinforcement Distribution Homogeneity in CNT/Metal Composites

      Paulo Rossi, Sebastian Suarez, Flavio Soldera and Frank Mücklich

      Article first published online: 23 DEC 2014 | DOI: 10.1002/adem.201400352

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      We show a direct method to assess the reinforcement homogeneity in composite materials. The method is based in the statistical analysis of the CNT-cluster distribution observed in micrographs. A relationship between the amount of CNT and the distribution homogeneity and the mechanical properties is noticed.

    15. Robust Superamphiphobic Nanoscale Copper Sheet Surfaces Produced by a Simple and Environmentally Friendly Technique

      Khedir R. Khedir, Zubayda S. Saifaldeen, Taha M. Demirkan, Alaa A. Al-Hilo, Matthew P. Brozak and Tansel Karabacak

      Article first published online: 10 DEC 2014 | DOI: 10.1002/adem.201400397

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      A novel, simple, and environmentally friendly technique of hot water treatment is used to introduce copper oxide nanostructures onto copper sheet surfaces. Analysis reveals that nanostructures are made of either cube-like Cu2O or leaf-like CuO. After surface energy reduction, superamphiphobic nanoscale copper sheet surfaces are obtained. The surfaces also show a high physical and chemical robustness.

  16. Full Paper

    1. Effect of High-Energy Electropulsing on the Phase Transition and Mechanical Properties of Two-Phase Titanium Alloy Strips

      Xiaoxin Ye, Zion T. H. Tse, Guoyi Tang and Guolin Song

      Article first published online: 10 DEC 2014 | DOI: 10.1002/adem.201400273

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      Rapid electropulsing-induced phase precipitation and ductility improvement are found in the two-phase Ti–6Al–4V alloy strips. The microstructure evolution and mechanical properties of this metallic material under the unique processing method are characterized and measured.

  17. Full Papers

    1. Strain Gradient in Micro-Hardness Testing and Structural Relaxation in Metallic Glasses

      Yannick Champion and Loïc Perrière

      Article first published online: 9 DEC 2014 | DOI: 10.1002/adem.201400423

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      Depth (h)-dependence of micro-hardness (Hv) is studied for the Zr55Cu20Al10Ni10Ti5 (figure) Ni53Nb20Zr8Ti10Co6Cu3 and Mg65Cu12.5Ni12.5MM10 metallic glasses, after thermal annealing and a modeling is proposed to describe observations. We show that hardness systematically decreases with annealing and emphasize the role of the shear bands and the elastic properties of the glass in the analyzed effects.

    2. Relevance of Carbon Dioxide Laser to Remove Scratches on Large Fused Silica Polished Optics

      Philippe Cormont, Antoine Bourgeade, Sandy Cavaro, Thierry Donval, Thomas Doualle, Gael Gaborit, Laurent Gallais, Laurent Lamaignère and Jean-Luc Rullier

      Article first published online: 9 DEC 2014 | DOI: 10.1002/adem.201400383

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      A carbon dioxide (CO2) laser is used to remove a long scratch on a fused silica window, which can be seen on the picture. This laser treatment is applied only locally on the scratch to melt the silica surface. After processing, the scratch is not visible anymore and the window is much more resistant to high power laser illumination.

    3. Development of High-Performance Mg Alloy via Introducing Profuse Long Period Stacking Ordered Phase and Stacking Faults

      Yufeng Jiao, Jinghuai Zhang, Yongbin Jing, Chi Xu, Shujuan Liu, Li Zhang, Longjiang Xu, Milin Zhang and Ruizhi Wu

      Article first published online: 9 DEC 2014 | DOI: 10.1002/adem.201400369

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      In this study, a new high-performance Mg–RE–Zn alloy is developed via introducing a large volume fraction of long-period stacking ordered (LPSO) phase in combination with nano-spaced stacking faults (SFs), and its ultimate tensile strength (UTS) and tensile yield strength (TYS) could reach 314 and 231 MPa at 300 °C.

    4. Microstructure and Mechanical Properties of Al/Graphene Composite Produced by High-Pressure Torsion

      Liyuan Zhao, Huimin Lu and Zhijiang Gao

      Article first published online: 26 NOV 2014 | DOI: 10.1002/adem.201400375

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      Ultrafine-grained Al/graphene composite has been fabricated using high-pressure torsion at room temperature. Graphene platelets act as obstacles pinning dislocations and blocking grain boundaries' movement, leading to grain refinement of the composite. And this composite shows smaller grain size and higher hardness and tensile strength than pure Al and Al/multi-walled carbon nanotubes composite.

    5. Active Vibration Damping in Structural Aluminum Die Castings via Piezoelectricity – Technology and Characterization

      Matthias Schwankl, Simon Kimme, Carina Pohle, Welf-Guntram Drossel and Carolin Körner

      Article first published online: 26 NOV 2014 | DOI: 10.1002/adem.201400367

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      The present work deals with the unique approach of integrating piezoelectric modules into aluminum castings. Applied casting technologies and insert manufacturing details are described. Results from experiments using microphones and LSV indicate a great damping effect at the first natural frequency (978 Hz) of the bell-like casting.

    6. Micro-Shaping, Polishing, and Damage Repair of Fused Silica Surfaces Using Focused Infrared Laser Beams

      Manyalibo J. Matthews, Steven T. Yang, Nan Shen, Selim Elhadj, Rajesh N. Raman, Gabe Guss, Isaac L. Bass, Michael C. Nostrand and Paul J. Wegner

      Article first published online: 26 NOV 2014 | DOI: 10.1002/adem.201400349

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      Localized infrared laser heating can effectively remove surface flaws, which limit performance in high power laser systems. Through direct thermal imaging and finite element modeling, we show how flaw repair can be achieved through thermal annealing or micro-machining methods. The wavelength-dependent optical constants and thermal diffusion time of the material are shown to be crucial in optimizing laser parameters.

    7. Self-Assembled Recyclable Hierarchical Bucky Aerogels

      Mehmet Karakaya, Deepika Saini, Ramakrishna Podila, Malcolm J. Skove, Apparao M. Rao, Ramathasan Thevamaran and Chiara Daraio

      Article first published online: 20 NOV 2014 | DOI: 10.1002/adem.201400414

      Thumbnail image of graphical abstract

      The bucky aerogel (BAG) is a 3D,interconnected, carbon nanotube based material that is capable of efficiently separating oil from water. Our facile and scalable top down approach allows a strong control of the porosity. BAG exhibits superhydrophobicity and oleophilicity, which when combined with its capillary action allows selective adsorption of various organic solvents up to 20 times its weight.

  18. Reviews

    1. Low-Density High-Strength Bulk Metallic Glasses and Their Composites: A Review

      Jian-Zhong Jiang, Douglas Hofmann, David John Jarvis and Hans-J. Fecht

      Article first published online: 19 NOV 2014 | DOI: 10.1002/adem.201400252

      Thumbnail image of graphical abstract

      This review gives an overview of recent accomplishments in the field of lightweight bulk metallic glasses/composites and their potential engineering and space applications. We mainly focus on four systems, namely, Al-, Mg-, Ca-, and Ti-based metallic glasses. Glass forming ability, mechanical properties, thermal stability, and corrosion resistance of the four metallic glass systems and their composites are presented.

  19. Full Papers

    1. On the Super-Elastic and Phase Transformation of a Novel Ni-Rich/NiTiCu Bi-Layer Thin Film

      Maryam Mohri, Mahmoud Nili-Ahmadabadi and Julia Ivanisenko

      Article first published online: 11 NOV 2014 | DOI: 10.1002/adem.201400284

      Thumbnail image of graphical abstract

      A novel bi-layer Ni-rich/Ti-rich thin film is deposited and crystallized. The bi-layer exhibits a two-step transformation B2 [LEFT RIGHT ARROW] R [LEFT RIGHT ARROW] B19’ with narrow thermal hysteresis. It presents a pseudo elastic effect and partial permanent strain because of composite structure. Its modulus and hardness values are between martensite and austenite phases.

    2. Morphology Evolution of ZnO Submicroparticles Induced by Laser Irradiation and Their Enhanced Tribology Properties by Compositing with Al2O3 Nanoparticles

      Guangbin Duan, Xilun Hu, Xiaoyun Song, Zhiwen Qiu, Haibo Gong and Bingqiang Cao

      Article first published online: 6 NOV 2014 | DOI: 10.1002/adem.201400385

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      A laser-stimulated surface tension energy release strategy is reported to grow metal oxide spherical particles using ZnO as example. The ZnO submicrospheres exhibit clear morphology-dependent friction reduction property but no anti-wear effect. However, the integrated application of ZnO submicrospheres and Al2O3 nanoparticles can improve both the friction-reduction and anti-wear properties.

  20. Communications

    1. Load Sharing Phenomena in Nanoscale Cu/Nb Multilayers

      Mikhail N. Polyakov, Jochen Lohmiller, Patric A. Gruber and Andrea M. Hodge

      Article first published online: 3 NOV 2014 | DOI: 10.1002/adem.201400368

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      By use of X-ray diffraction, the load-bearing contributions of nanometer-thick Cu and Nb layers in Cu/Nb multilayer composites are isolated. The Cu bears higher stresses at failure and the Nb bears lower stresses at failure with decreasing Cu layer thickness. The Cu and Nb layers appear to have independent deformation mechanisms.

  21. Full Papers

    1. In Situ Reinforcement of Ti6Al4V Matrix Composites by Polymer-Derived-Ceramics Phases

      Alberto Fabrizi, Franco Bonollo, Paolo Colombo and Lisa Biasetto

      Article first published online: 3 NOV 2014 | DOI: 10.1002/adem.201400362

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      Ti5Si3 and TiC reinforcing phases are formed in situ within a Ti6Al4V matrix via powder metallurgy technique and preceramic polymers precursors. The hardness and wear resistance are significantly increased compared to standard Ti6Al4V cast alloy (Vickers hardness is doubled and volume loss is ≈87% less than standard Ti6Al4V).

  22. Communications

    1. Enhanced Plasticity via Kinking in Cubic Metallic Nanolaminates

      Thomas Nizolek, Nathan A. Mara, Irene J. Beyerlein, Jaclyn T. Avallone and Tresa M. Pollock

      Article first published online: 15 OCT 2014 | DOI: 10.1002/adem.201400324

      Thumbnail image of graphical abstract

      Kink band formation is unexpected in cubic nanocrystalline metals but is found to occur during layer-parallel compression of bulk Cu–Nb nanolaminates produced by the accumulative roll bonding process. This deformation mechanism is strongly length scale dependent and allows for large compressive strains (>25%) at high stresses high stresses (>1 GPa) without leading to crack formation.

    2. Grain Growth and β to α Transformation Behavior of a β-Solidifying TiAl Alloy

      Thomas Klein, Salar Niknafs, Rian Dippenaar, Helmut Clemens and Svea Mayer

      Article first published online: 15 OCT 2014 | DOI: 10.1002/adem.201400336

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      Intermetallic γ-TiAl-based alloys are promising materials for light-weight structures in high-temperature application. Their material properties are highly dependent on the microstructural evolution during heat treatments. High-temperature laser-scanning confocal microscopy (HTLSCM) is applied for studying grain growth in the single β phase region and β to α phase transformation allowing for the in situ visualization of the microstructural evolution.

  23. Full Papers

    1. Strain-Induced Phase Transformation of MCrAlY

      Christine Borchers, Thorsten Stoltenhoff, Matthias Hahn, Matthias Schulze, Hamid Assadi, Challapalli Suryanarayana, Frank Gärtner and Thomas Klassen

      Article first published online: 15 OCT 2014 | DOI: 10.1002/adem.201400174

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      Cold spraying results in extensive phase transformation from bcc to fcc structure in an MCrAlY powder (5–22 μm). The coating is dense, see figure, and nanocrystalline. Ball milling of the same powder results in bcc to fcc phase transformation, too, though without evidence of nanocrystallization.

    2. High Temperature Oxidation Behavior of Hypoeutectic Mg–Sr Binary Alloys: The Role of the Two-Phase Microstructure and the Surface Activity of Sr

      Deniz S. Aydin, Zeynel Bayindir and Mihriban O. Pekguleryuz

      Article first published online: 10 OCT 2014 | DOI: 10.1002/adem.201400191

      Thumbnail image of graphical abstract

      The high temperature oxidation resistance of pure Mg is improved with the modification of the oxide scale on the surface via alloying. Sr as a surface active element in Mg changes the oxide structure and forms a compact MgO + SrO composite oxide scale with a SrO rich outermost layer.

  24. Communications

    1. Novel Adhesion Promoter for Metal–Plastic Composites

      Alexandra Yulinova, Mandy Göring, Daniela Nickel, Stefan Spange and Thomas Lampke

      Article first published online: 8 OCT 2014 | DOI: 10.1002/adem.201400366

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      This work presents a novel bonding agent for metal–plastic composites produced by twin polymerization. During twin polymerization, an interpenetrated network of organic and inorganic homopolymers is formed from one twin monomer. The mixtures of two twin monomers with various mixing ratios are studied. The suitability of a twin polymer as adhesion promoter is evaluated by axial loading tensile tests.

  25. Full Papers

    1. A Systematic Approach for the Modeling of Replicated Foams

      Mehrad Mousavi Rahimi and Sharif Shahbeyk

      Article first published online: 3 OCT 2014 | DOI: 10.1002/adem.201400330

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      This paper intends to provide grounds for more realistic numerical modeling of replicated foams by simulating the actual manufacturing processes of preparing a porous preform, filling free spaces with foam material, and dissolving space-holders. Moreover, a simple numerical method is introduced to consider the effect of infiltration pressure on the microstructure of replicated foams.

  26. Communications

    1. A New Approach to Refine Grains in Al Alloys

      Zhihao Bai, Feng Qiu, Tao Zhang and Qichuan Jiang

      Article first published online: 3 OCT 2014 | DOI: 10.1002/adem.201400318

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      A new refining grains strategy is reported. A significant refining effect of α-Al grain from 180 to 32 μm can be achieved by adding 0.2 wt.% Zr55Cu30Al10Ni5 metallic glass into Al–Cu melt. This remarkable refinement effect is mainly attributed to the Zr2Cu and ZrCu(B2) crystallization phases, and they will act as the heterogeneous nucleation sites for α-Al grains because of their high melt points, small, uniform sizes and good lattice mismatch with α-Al matrix.

  27. Full Papers

    1. Structure–Property–Processing Relationships for Stainless Steel Foams Made by Mechanical Aeration of Powder Slurries

      Xi Lin and Andrew R. Kennedy

      Article first published online: 29 SEP 2014 | DOI: 10.1002/adem.201400214

      Thumbnail image of graphical abstract

      A simple process, based on the mechanical aeration of a powder slurry, followed by gel casting and sintering, has been used to produce stainless steel metal foams. The foams have spherical pores, connected by windows, to create an interconnected, open cell structure. Despite the simplicity of the process, the foams have good and reproducible foam structures and compressive mechanical properties.

  28. Communications

    1. Importance of Bimodal Structure Topology in the Control of Mechanical Properties of a Stainless Steel

      Zhe Zhang, Dmitry Orlov, Sanjay Kumar Vajpai, Bo Tong and Kei Ameyama

      Article first published online: 29 SEP 2014 | DOI: 10.1002/adem.201400358

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      Creating bimodal grain size distribution in crystalline materials is an effective strategy to improve structural efficiency. Present investigation demonstrates that further control over topology through the formation of bimodal ‘harmonic’ structure simultaneously increases average values of strength and ductility, reduces the variation of corresponding properties, and thwarts the localization of plastic flow.

  29. Full Papers

    1. Carbon-Dioxide Laser Beam Polishing of Fused Silica Surfaces – Process Development and Optimization

      Kerstin Hecht, Jens Bliedtner, Matthias Rost, Hartmut Müller and Thomas Schmidt

      Article first published online: 22 SEP 2014 | DOI: 10.1002/adem.201400363

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      We present a process development and application for laser polishing of fused silica. Many parameters and environmental conditions influence the surface condition as well as the final quality. Thus, it is necessary to examine and optimize the finishing technique using different analyzing methods.

    2. Spark Plasma Sintering and Characterization of Graphene Platelet/Ceramic Composites

      Kyle Jiang, Jiran Li and Jian Liu

      Article first published online: 22 SEP 2014 | DOI: 10.1002/adem.201400326

      Thumbnail image of graphical abstract

      Alumina (Al2O3) and zirconia (ZrO2) toughened Al2O3 (ZTA) composites reinforced with GPLs were fabricated respectively using spark plasma sintering. The addition of GPLs hinders the growth of the ceramic matrix grains and help form homogenous microstructures of the ceramic matrices. Approximately, a 26.4 and a 29% improvements in fracture toughness were achieved for GPL/Al2O3 and GPL/ZTA composites, respectively.

  30. Reviews

    1. Recent Progress on Magnetorheological Solids: Materials, Fabrication, Testing, and Applications

      Ubaidillah, Joko Sutrisno, Agus Purwanto and Saiful Amri Mazlan

      Article first published online: 22 SEP 2014 | DOI: 10.1002/adem.201400258

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      The functional behavior of MREs is briefly explained. The art of the materials provides the current position and mapping of the matrix and filler particles. Types of matrix and particles are mentioned together with the level of the research interest on MREs. Description of the fabrication is provided in simple diagrams as summarized from previous works to enhance the MREs performance. The possible tests to reveal the characteristics of the MREs are delivered with the global experimental setup. The review also explains the applications of MREs as well as discussion on the MREs future promising applications.

  31. Full Paper

    1. Influence of YH2 Nanoparticles Addition on the Microstructure and Mechanical Properties of Oxide Dispersion Strengthened Ferritic Alloys

      Tong Liu, Chenxi Wang, Hailong Shen, Yurong Cao and Wusheng Chou

      Article first published online: 19 SEP 2014 | DOI: 10.1002/adem.201400299

      Thumbnail image of graphical abstract

      YH2 nanoparticles are used as raw particles to substitute the conventional Y2O3 nanoparticles in the Al-containing ODS steels. Y2Ti2O7 nanoparticles in coherent with α-Fe matrix are generated and the mean size of the oxide particles is successfully decreased. The tensile strength of the ODS steel increases with the addition of YH2.

    2. Self-Catalytic Growth of β-Ga2O3 Nanostructures by Chemical Vapor Deposition

      Sudheer Kumar, Christian Tessarek, George Sarau, Silke Christiansen and Rajendra Singh

      Article first published online: 17 SEP 2014 | DOI: 10.1002/adem.201400289

      Thumbnail image of graphical abstract

      Self catalytic growth of beta-gallium oxide (β-Ga2O3) nanostructures has been reported. The detail structural, morphological and optical analyses of as-grown nanostructures are carried out using various techniques such as X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, Raman and cathodoluminescence. The as-grown nanostructures are monoclinic and single crystalline with excellent optical properties.

  32. Full Papers

    1. Purification of Carbon Nanotube Sheets

      Yi Lin, Jae-Woo Kim, John W. Connell, Marisabel Lebrón-Colón and Emilie J. Siochi

      Article first published online: 12 SEP 2014 | DOI: 10.1002/adem.201400306

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      Purification of carbon nanotube macroscopic assemblages such as sheets presents additional challenges in comparison to that established for powdery carbon nanotubes. It is demonstrated that large-sized carbon nanotube sheets can be effectively purified to remove residual metal catalysts while retaining their structural integrity and mechanical properties for their use in structural composites.

  33. Communications

    1. Guiding and Deflecting Cracks in Bulk Metallic Glasses to Increase Damage Tolerance

      Jun Yi, Wei Hua Wang and John J. Lewandowski

      Article first published online: 3 SEP 2014 | DOI: 10.1002/adem.201400209

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      Pre-existing shear bands (PESBs) are introduced at stress concentration of bulk metallic glasses. Such PESBs channel and guide cracks to deflect beyond plastic zone in which stress is concentrated while cavitation is inhibited during crack propagation. As a result, the fracture resistance of bulk metallic glasses is improved significantly.

  34. Full Papers

    1. Low-Molecular Mass Organic Gelcasting of Titanium Hydride to Prepare Titanium

      Qing Ye, Zhimeng Guo, Boxin Lu, Junpin Lin and Huiping Shao

      Article first published online: 3 SEP 2014 | DOI: 10.1002/adem.201400253

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      Low-molecular mass organic gelcasting is firstly utilized to fabricate titanium structural materials. The aim is to find a low-residual gel system for the fabrication of titanium with good ductility. The thermally reversible gel system is composed of 1,3:2,4-dibenzylidene sorbitol (gelator) and 1-butanol (solvent). Rosin is used to increase the green strength. After sintering, the contents of oxygen and carbon contamination are 0.31 and 0.08 wt%, respectively, which contribute to a high-level of mechanical property with tensile strength of 580 MPa and elongation of 8%. Eventually, titanium parts with complex shape are successfully prepared.

    2. Dynamic Recrystallization of Wrought–Solidified–Wrought Complex Structure in Ni-Based Superalloys

      Yongquan Ning, Bingchao Xie, Hui Li and Ming Wang Fu

      Article first published online: 29 AUG 2014 | DOI: 10.1002/adem.201400223

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      Electron beam welding is conducted, and wrought–solidified–wrought complex structure is machined from the central part of the weldments. Dislocations drive the occurrence of DRX. Solidified dendrite can be greatly eliminated and refined after hot deformation due to repeating occurrence of DRX.

    3. X-Ray Photoelectron Spectroscopy Investigations of the Surface Reaction Layer and its Effects on the Transformation Properties of Nanoscale Ti51Ni38Cu11 Shape Memory Thin Films

      Dennis König, Dennis Naujoks, Teresa de los Arcos, Simon Grosse-Kreul and Alfred Ludwig

      Article first published online: 28 AUG 2014 | DOI: 10.1002/adem.201400317

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      Ti51Ni38Cu11 thin films of different film thickness are investigated regarding the influence of the reaction layers on the chemical composition of the transforming phase and the corresponding functional properties. A model is proposed describing the different reaction layers on the surface of the thin film and at the substrate/thin film interface.

    4. Microstructures and Properties of Graphene-Cu/Al Composite Prepared by a Novel Process Through Clad Forming and Improving Wettability with Copper

      Zhan Yong Zhao, Ren Guo Guan, Xi Hua Guan, Zhen Xian Feng, Hui Chen and Yu Chen

      Article first published online: 21 AUG 2014 | DOI: 10.1002/adem.201400173

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      An improved method is adopted to prepare graphene-Cu as an enhancement phase. A graphene-Cu reinforced pure aluminum composite is prepared by clad rolling. The graphene-Cu are distributed homogeneously in the composite. Mechanical properties of the graphene-Cu/Al composite are higher than that of the aluminum matrix.

    5. Preparation and Thermal Conductivity of Spark Plasma Sintered Aluminum Matrix Composites Reinforced with Titanium-Coated Graphite Fibers

      Tingting Liu, Xinbo He, Qian Liu, Shubin Ren, Lin Zhang and Xuanhui Qu

      Article first published online: 14 AUG 2014 | DOI: 10.1002/adem.201400148

      Thumbnail image of graphical abstract

      The figure shows the effect of fiber volume fraction on thermal conductivity (TC) of uncoated and Ti-coated graphite fiber (Grf)/Al composites. All the Ti-coated composites possess higher TC than pure Al and uncoated ones. Particularly, the TC of 50 vol% Ti-coated composite is increased to 238 W m−1 K−1, nearly 16% higher than that of pure Al and twice as high as that of the uncoated one.

  35. Communication

    1. Narrow Conductive Structures with High Aspect Ratios Through Single-Pass Inkjet Printing and Evaporation-Induced Dewetting

      Robert Abbel, Pit Teunissen, Jasper Michels and Wilhelm A. Groen

      Article first published online: 14 AUG 2014 | DOI: 10.1002/adem.201400339

      Thumbnail image of graphical abstract

      Inkjet printed silver lines contract to widths below 20 μm during drying on an organic planarization coating. Aspect ratios previously unprecedented with single pass inkjet printing on isotropic homogeneous substrates are obtained. This effect is caused by the subsequent evaporation of solvents from the ink, which results in a continuous increase of its surface tension and thus controlled dewetting.

    2. Influence of the Matrix Composition and the Processing Conditions on the Grain Size Evolution of Nextel 610 Fibers in Ceramic Matrix Composites after Heat Treatment

      Eike Vokmann, Marcelo D. Barros, Kamen Tushtev, Walter E.C. Pritzkow, Dietmar Koch, Jürgen Göring, Christian Wilhelmi, Georg Grathwohl and Kurosch Rezwan

      Article first published online: 14 AUG 2014 | DOI: 10.1002/adem.201400220

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      The mechanical performance of ceramic matrix composites (CMC) is strongly related to the properties of the reinforcement. In case of the polycrystalline alumina Nextel® 610, these are dominated by the grain structure of the fiber. Within this study we show, that the surrounding matrix material and the processing conditions exert a high impact on the microstructure of the fibers. Therefore, different matrices and manufacturing methods can result in different fiber structures and performances.

  36. Full Paper

    1. Influence of Iridium on the Properties of γ′-Strengthened Co-Base Superalloys

      Alexander Bauer, Steffen Neumeier, Florian Pyczak and Mathias Göken

      Article first published online: 13 AUG 2014 | DOI: 10.1002/adem.201400266

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      Addition of Iridium to a γ′ strengthened Co-base superalloy leads to increased volume fraction and solvus temperature of the γ′ precipitate phase, as well as to higher solidus and liquidus temperatures. Iridium partitions slightly to the γ′ precipitate phase and the creep strength is improved considerably as long the γ/γ′-microstructure is not discontinuously transformed.

  37. Full Papers

    1. Direct Crystallization of Silicoaluminophosphates onto the Surface of Open-Celled SiC Foam

      Carolin Bauer, Franziska Scheffler and Michael Schwidder

      Article first published online: 4 AUG 2014 | DOI: 10.1002/adem.201400278

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      Due to their 3D fluid permeability open-celled ceramic foams are promising carriers for microporous materials e.g. for catalytic and heat storage applications. Therefore, an efficient coating process is of great interest. In case of zeolites, an elegant way is the crystallization directly onto the surface. In this work, SAPO-34 and SAPO-5 are deposited onto the surface of SiC foam by this method.

    2. Functional Surface Layers on Stainless Steels Generated by Means of EB Cladding and Nitrocarburizing

      Anke Dalke, Anne Jung, Heinz-Joachim Spies, Rolf Zenker and Joachim Lerche

      Article first published online: 1 AUG 2014 | DOI: 10.1002/adem.201400121

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      A combined surface treatment of electron beam cladding and subsequent plasma nitrocarburizing of a duplex stainless steel combines high wear behavior and good corrosion resistance. CoCr-based EB coatings exhibit hardness values of up to 500 HK0.01 and give mechanical support to the thin, hard expanded austenite layer. Hardness-depth profiles and wear tests prove the high efficiency of the surface compound. The wear coefficient is reduced for 2 orders of magnitude.

    3. The Structubent: A Nanocomposite Solution to Compressed Natural Gas Storage

      Steven Shimizu and Michael S. Strano

      Article first published online: 28 JUL 2014 | DOI: 10.1002/adem.201400038

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      This study proposes the use of a structubent layer, composed of methane adsorbent particles and a structural matrix, as a liner for compressed natural gas (CNG) pressure vessels. The volume- and mass-specific methane capacities are compared with that of regular CNG and pure adsorbent systems, showing the structubent concept to be favorable under certain conditions.

    4. Intermetallic Layer Growth Kinetics in Sn-Ag-Cu System using Diffusion Multiple and Reflow Techniques

      Magdalena Pawełkiewicz, Marek Danielewski and Jolanta Janczak-Rusch

      Article first published online: 22 JUL 2014 | DOI: 10.1002/adem.201400226

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      The diffusion multiple (solid state) and the reflow soldering (solid and liquid state) techniques are used to study the diffusion controlled reactions in Sn-Ag-Cu system. The microstructural evolution at the interfaces, the kinetic rate constants and the respective activation energies of the Cu6Sn5 and Cu3Sn phases in the temperature range between 150 and 200 °C are presented.

    5. Evaluating the Room Temperature ECAP Processing of a NiTi Alloy via Simulation and Experiments

      Hamed Shahmir, Mahmoud Nili-Ahmadabadi, Mojtaba Mansouri-Arani, Ali Khajezade and Terence G. Langdon

      Article first published online: 19 JUL 2014 | DOI: 10.1002/adem.201400248

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      The present investigation is initiated to fully evaluate the deformation behavior of a NiTi alloy by simulation and experiments after successfully processing by equal-channel angular pressing (ECAP) through one and two passes using a core–sheath billet design. The presented results show a high level of hardness and stored energy after processing through two passes with good homogeneity.

    6. Enhanced Multifunctional Properties of Graphene Nanocomposites with Nacre-Like Structures

      Liang Yan, Ya-Nan Chang, Wenyan Yin, Gan Tian, Liangjun Zhou, Zhongbo Hu, Gengmei Xing, Zhanjun Gu and Yuliang Zhao

      Article first published online: 17 JUL 2014 | DOI: 10.1002/adem.201400237

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      Multifunctional graphene nanocomposites are prepared by integrating magnetic and lanthanide-doped luminescent nanocrystals into the GO matrix and then vacuum filtration. The obtained nanocomposites with a nacre-like structure have the GO flexibility and enhanced multifunctionality, including luminescent, magnetical, and mechanical properties. In particular, compared with the pure GO film, the maximum tensile strength (102.8 MPa) and modulus (10.9 GPa) of the nanocomposite increase by ca. 119 and 160%, respectively. The luminescent, magnetic, and mechanical properties of the nanocomposites can be fine-tuned by changing the graphene-to-nanocrystal ratios.

    7. The Thermal Stability of Intermetallic Compounds in an As-Cast SX Co-Base Superalloy

      Inmaculada Lopez-Galilea, Christopher Zenk, Steffen Neumeier, Stephan Huth, Werner Theisen and Mathias Göken

      Article first published online: 17 JUL 2014 | DOI: 10.1002/adem.201400249

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      This work studies the nature and stability of three intermetallic phases – Laves, B2 and needle-shaped precipitates – in a multi-component γ/γ′ Co-base superalloy, named ERBO-Co0. These phases are generated during casting at the interdendritic areas. Experimental characterization of intermetallic phases is contrasted with thermodynamic calculations, which predicts the presence of the identified phases.

    8. One-Step Fabrication of Nanocomposite Thin Films of PTFE in SiOx for Repelling Water

      Kamil Zuber, Peter Murphy and Drew Evans

      Article first published online: 16 JUL 2014 | DOI: 10.1002/adem.201400171

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      Robust, transparent, water repelling thin films are deposited onto a range of different substrates (from solids, to fibrous materials, to liquids) using an atmospheric plasma process. The thin films represent the one-step fabrication of nanocomposites combining PTFE particles in a siloxane glass matrix.

    9. High Enhanced Efficiency and Mechanism of Ultra-Long SiC Nanowires in Composites

      Jian Wei, Kezhi Li, Hudie Yuan and Rui Hao

      Article first published online: 10 JUL 2014 | DOI: 10.1002/adem.201400194

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      Silicon carbide nanowires have attracted much attention due to their excellent enhanced property in advanced nanocomposites. In this paper, ultra-long SiC nanowires with large aspect ratio of 2 × 104–5 are incorporated successfully into epoxy resin to evaluate their enhanced efficiency. The results indicate that 9.7 and 13.3% bending strength increases are achieved for the composites with the addition of very small quantity (0.1 and 0.125 wt%) of ultra-long SiC nanowires. The ultra-long SiC nanowires have the highest enhanced efficiency than other shorter ones in epoxy resin composites.

    10. Carbon Nanotube–Chitosan Composite Beads with Radially Aligned Channels and Nanotube-Exposed Walls for Bilirubin Adsorption

      An Ouyang, Qianming Gong and Ji Liang

      Article first published online: 10 JUL 2014 | DOI: 10.1002/adem.201400250

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      Spherical chitosan–CNT composite beads fabricated via freeze-casting result in highly porous structures with radially oriented channels. We have observed localized regions of small CNT agglomerates embedded within the chitosan matrix at a lower CNT loading, and predominately exposed CNTs distributed throughout the channel walls at a higher loading. These beads show great adsorption capacity to bilirubin as efficient hemoadsorbents.

    11. Improved Description of the Flow Characteristics of Copper for the Finite Element Simulation of the Cold Joining Process for High Current Electrical Contacts

      Ekine Aristizabal, Friedhelm Günter, Marcus Hopfeld and Peter Schaaf

      Article first published online: 10 JUL 2014 | DOI: 10.1002/adem.201400096

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      This article studies the strengthening mechanisms that occur in copper components due to die cutting, and quantifies them by means of nanoindentation. These hardness distributions and an inhomogeneous material law are implemented in a commercial FE-simulation tool. The new material description delivers an improved agreement between experiment and simulation in a small-punch test.

    12. Crystallization of Zr55Cu30Al10Ni5 Bulk Metallic Glass in Laser Welding: Simulation and Experiment

      Biao Chen, Tielin Shi, Mo Li, Chi Wen and Guanglan Liao

      Article first published online: 10 JUL 2014 | DOI: 10.1002/adem.201400145

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      The Kissinger analysis and temperature field simulation are combined to predict the crystallization of laser welding for Zr55Cu30Ni5Al10 bulk metallic glass. For validation, the laser welding experiments are conducted. The experimental results are consistent with the simulation, indicating that the Kissinger analysis and simulation of temperature field can be used to predict the crystallization.

    13. Corrosion Behavior of Nano/Sub-Micron F401 Titanium Alloy

      Eli Aghion, Inbar Guinguis and Jeremy Goldman

      Article first published online: 10 JUL 2014 | DOI: 10.1002/adem.201400147

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      Modifying conventional Ti alloys to impart nanostructural features holds promise for improving specific strength. Here, we show that grain refinement in an F401 alloy increases the mechanical strength without impairing the excellent corrosion resistance, relative to the conventional Ti–6Al–4V alloy.

    14. Tungsten (W) Laminate Pipes for Innovative High Temperature Energy Conversion Systems

      Jens Reiser, Michael Rieth, Anton Möslang, Henri Greuner, David E. J. Armstrong, Thorsten Denk, Tim Gräning, Wolfgang Hering, Andreas Hoffmann, Jan Hoffmann, Harald Leiste, Tobias Mrotzek, Reinhard Pippan, Werner Schulmeyer, Tobias Weingärtner and Anton Zabernig

      Article first published online: 7 JUL 2014 | DOI: 10.1002/adem.201400204

      Thumbnail image of graphical abstract

      By cold working the brittle-to-ductile transition temperature (BDTT) of tungsten can be shifted to lower temperatures. The authors make use of this fact by using a tungsten foil for the synthesis of tungsten laminate pipes. These pipes show extraordinary mechanical properties and are a serious candidate to be used in innovative high temperature energy conversion systems (Figure).

  38. Communications

    1. Thermophysical Properties of Lanthanum–Gadolinium Zirconate and Gadolinia-Stabilized Zirconia Nanocomposite from In Situ Reaction

      Songbai Liu, Lilin Zhao and Kuo Jiang

      Article first published online: 4 JUL 2014 | DOI: 10.1002/adem.201400164

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      Nano-composite ceramic composing of (La0.66Gd0.34)2Zr2O7 (LGZ) and (Zr0.76Gd0.24)O1.88 (GSZ) phases is synthesized form in-situ reaction and is consolidated by spark plasma sintering. It has a thermal conductivity about 20 and 35% lower than that of single phase LGZ and GSZ materials, respectively. The lower thermal conductivity is attributed to the thermal resistance effect of phase boundary.

  39. Full Papers

    1. Microstructure and Mechanical Properties of Laser Beam Welded Joints between Fine-Grained and Standard Ti-6Al-4V Sheets Subjected to Superplastic Forming

      Nikolai Kashaev, Volker Ventzke, Manfred Horstmann, Stefan Riekehr, Grigory Yashin, Lennart Stutz and Werner Beck

      Article first published online: 2 JUL 2014 | DOI: 10.1002/adem.201400202

      Thumbnail image of graphical abstract

      Microstructural and mechanical properties of laser welded butt joints between fine-grained (FG) and standard (STD) Ti–6Al–4Vare investigated to determine their behavior under static and cyclic loads and for superplastic forming. The effect of the strength mismatch is that the plastic deformation of the FG-STD butt joint is determined by the lower strength of the Ti–6Al–4VSTD base material.

  40. Communications

    1. Fabrication of Mechanically Tissue-Like Fibrous Poly(xylitol sebacate) Using Core/Shell Electrospinning Technique

      Yuan Li and Qi-Zhi Chen

      Article first published online: 1 JUL 2014 | DOI: 10.1002/adem.201400230

      Thumbnail image of graphical abstract

      Chemically crosslinked elastomer poly(xylitol sebacate)(PXS) is for the first time electrospun into fibrous mats. The PXS2:5 fibre mats show nonlinear J-shaped stress-strain curves, with large average rupture elongation (≈75%). The newly developed porous PXS scaffolds show tissue-like mechanical properties and excellent biocompatibility, making them very promising for bioengineering of very soft tissues and organs.

  41. Reviews

    1. Development and Application of Multi-Scale Numerical Tool to Modeling Pneumatic Ventricular Assist Devices with Increased Athrombogenicity

      Magdalena Kopernik

      Article first published online: 24 JUN 2014 | DOI: 10.1002/adem.201400157

      Thumbnail image of graphical abstract

      The two-scale model of polymeric ventricular assist device with deposited biocompatible TiN nano-coating is introduced (figure). The FE macro-model and the RVE micro-model are developed to optimize and determine the crucial parameters of the device in both scales. The digital image correlation, in situ SEM’s micro-tensile test, AFM’s images, nanoindentation test, and tensile tests supply data for the multi-scale numerical tool.

  42. Communications

    1. Remarkable Improvement of Shape Memory Effect in Austenitic Stainless Steel by Thermo-Mechanical Training

      Jie Chen, Huabei Peng, Shanling Wang, Yangyang Du and Yuhua Wen

      Article first published online: 27 MAY 2014 | DOI: 10.1002/adem.201300482

      Thumbnail image of graphical abstract

      This figure shows the shape recovery ratio as a function of thermo-mechanical training cycles when 304 stainless steel are deformed by 1.7% at 77 K. It shows that the thermo-mechanical training consisting of deformation at 178 K and subsequent annealing at 933 K remarkably enhances the shape memory effect of 304 stainless steel.

  43. Full Papers

    1. Fracture Morphologies of Zr-Based Bulk Metallic Glasses Under Different Stress States

      Shun Hua Chen, Kang Cheung Chan and Lei Xia

      Article first published online: 26 MAY 2014 | DOI: 10.1002/adem.201300426

      Thumbnail image of graphical abstract

      Fracture morphologies provide significant evidences in understanding the deformation and fracture mechanisms in bulk metallic glasses. When the applied uniform tensile stress is changed to a gradient distribution, the fracture surface shows enlarged smooth regions as well as the formation of some transition zones. The findings reveal that the stress gradient is able to confine the catastrophic failure of bulk metallic glasses.

    2. Characterization of Rapidly Solidified Nd–Al and Nd–Ag Eutectic Alloys in Drop Tube

      Uğur Büyük, Mustafa Erol, Thomas Volkmann and Dieter M. Herlach

      Article first published online: 22 MAY 2014 | DOI: 10.1002/adem.201400131

      Thumbnail image of graphical abstract

      Nd-14.2at%Al and Nd-20.0at%Ag eutectic alloys are solidified in an 8 m-drop tube and droplets in diameter of 100–900 μm are produced. The cooling rates, Nusselt, Reynolds, and Prandtl numbers are determined by heat balance calculations. Microstructures are analyzed, shown in the figure and eutectic spacings are determined. Microhardness is measured to reveal the cooling rate dependence of the droplets.

    3. Strain-Induced Alignment Mechanisms of Carbon Nanotube Networks

      Rebekah Downes, Shaokai Wang, David Haldane, Andrew Moench and Richard Liang

      Article first published online: 21 MAY 2014 | DOI: 10.1002/adem.201400045

      Thumbnail image of graphical abstract

      Individual carbon nanotubes (CNTs) possess remarkable mechanical properties that are mostly lost when the CNT networks are randomly oriented. When alignment is induced on the network using an application of a resin treatment and uniaxial strain, dramatically improved properties can be realized. CNT network's microstructure changes through strain strengthening mechanics are discussed.

  44. Communications

    1. Optimal Design of a Multifunctional Sandwich Panel With Foam Core: Lightweight Design for Flexural Stiffness and Acoustical Transmission Loss

      Pierre Leite, Marc Thomas, Frank Simon and Yves Bréchet

      Article first published online: 16 MAY 2014 | DOI: 10.1002/adem.201400075

      Thumbnail image of graphical abstract

      The use of a soft material, such as foam, as core in a sandwich panel offers increased acoustical transmission loss at the expense of a decrease of flexural stiffness. A genetic algorithm is used to explore the possible trade-off between mechanical and acoustical properties of foam core sandwich panels in a minimum weight design.

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