Advanced Engineering Materials

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  1. Full Papers

    1. Precipitation in a Nanograined 7475 Aluminium Alloy—Processing, Properties and Nanoanalysis

      Malgorzata Lewandowska, Kinga Wawer, Pawel Kozikowski, Masato Ohnuma and Krzysztof J. Kurzydlowski

      Article first published online: 17 APR 2014 | DOI: 10.1002/adem.201400018

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      Precipitation strengthening in a nanograined 7475 aluminium alloy obtained by hydrostatic extrusion of water quenched samples is studies. Low temperature ageing causes precipitation processes and strengthening phenomena. However, the particle strengthening is limited by enhanced grain boundary precipitation and smaller size of precipitates.

    2. A New In Situ Microscopy Approach to Study the Degradation and Failure Mechanisms of Time-Dependent Dielectric Breakdown: Set-Up and Opportunities

      Zhongquan Liao, Martin Gall, Kong Boon Yeap, Christoph Sander, Oliver Aubel, Uwe Mühle, Jürgen Gluch, Sven Niese, Yvonne Standke, Rüdiger Rosenkranz, Markus Löffler, Norman Vogel, Armand Beyer, Hans-Jürgen Engelmann, Peter Guttmann, Gerd Schneider and Ehrenfried Zschech

      Article first published online: 17 APR 2014 | DOI: 10.1002/adem.201400088

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      An in situ approach using transmission X-ray microscopy and scanning transmission electron microscopy is developed to study the degradation and failure mechanisms of time dependent dielectric breakdown (TDDB) in copper/ultra-low-k interconnects. The metal migration is detected by the bright field imaging, and the Cu distribution is shown by the electron spectroscopic imaging. This approach contributes the improved understanding of the TDDB.

    3. Spark Plasma Sintering of Alumina Composites with Graphene Platelets and Silicon Carbide Nanoparticles

      Jian Liu, Zheng Li, Haixue Yan and Kyle Jiang

      Article first published online: 16 APR 2014 | DOI: 10.1002/adem.201300536

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      Alumina (Al2O3) ceramic composites with graphene platelets (GPLs) and silicon carbide (SiC) nanoparticles were fabricated using spark plasma sintering furnace. The addition of GPLs and SiC significantly reduce the grain size of the Al2O3 matrix. Compared with pure Al2O3, the composites show approximately a 36% increase in hardness, a 40% increase in flexural strength and a 50% increase in fracture toughness.

    4. Low Temperature Processing of Reaction-Bonded Boron Carbide Composites

      Nachum Frage, Shmuel Hayun, Helen Dilman and Moshe P. Dariel

      Article first published online: 16 APR 2014 | DOI: 10.1002/adem.201400108

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      A novel approach for fabrication of reaction bonded B4C-(Al, Mg) composites at low temperature is described. The key feature of this approach is the uses of Mg-vapor atmosphere during the infiltration process. Low temperature process allows preventingthe formation of the deleterious aluminum carbide (Al4C3).

    5. Characterization and Modeling of Failure Initiation in Bainite-Aided DP Steel

      Ali Ramazani, Yuling Chang and Ulrich Prahl

      Article first published online: 15 APR 2014 | DOI: 10.1002/adem.201300556

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      Martensite cracking is identified as domain mechanism for failure initiation in bainite-aided DP steel. RVE approach combined with XFEM is used to model martensite cracking on mesoscale. XFEM is used to model martensite cracking. XFEM parameters are quantitatively identified and validated by numerical versus experimental tensile test comparison.

    6. Electrochemical and Mechanical Effects of Acid and Thermal Treatments of Carbon Fiber

      Sumin Li, Yutao Zhao, Zhao Zhang, Hua Tang, Haojie Song and Yaping Wang

      Article first published online: 15 APR 2014 | DOI: 10.1002/adem.201400033

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      Structural carbon fibers are gaining importance in multifunctional structural energy-storage composites. Surface modification of carbon fiber is essential to improve its energy storing ability. The PAN-based carbon fibers are subjected to acid and thermal oxidation to improve the supercapacitive performance.

  2. Communications

    1. Thermophysical Properties and Sintering of Ytterbia-Stabilized Tetragonal Zirconia Ceramic

      Kuo Jiang and Songbai Liu

      Article first published online: 15 APR 2014 | DOI: 10.1002/adem.201400065

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      Metastable tetragonal (t′) ZrO2 stabilized with 4 mol% Yb2O3 sinters more slowly and has a higher resistance to destabilization than YSZ with the same composition (4 mol% Y2O3). The improved phase stability is attributed to the slower diffusion of the smaller Yb3+ ion in t′ phase compared to the larger Y3+ ion. In addition, the TEC of 4 mol% Yb2O3-stabilized ZrO2 is also found to be superior to that of YSZ, suggesting practical possibility for thermal barrier coatings.

  3. Full Papers

    1. In Situ High Energy X-Ray Diffraction for Investigating the Phase Transformation in Hot Rolled TRIP-Aided Steels

      Piyada Suwanpinij, Andreas Stark, Xiaoxiao Li, Frank Römer, Klaus Herrmann, Thomas Lippmann and Wolfgang Bleck

      Article first published online: 9 APR 2014 | DOI: 10.1002/adem.201300537

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      A 100 keV X-ray beam is employed to diffract through TRIP steel samples during the hot rolling process simulation in a deformation dilatometer. The phase transformation and carbon partitioning are quantified in-situ from the diffraction pattern. The effect of pre-deformation on the transformation kinetics and the final amount of retained austenite is analyszed.

    2. Microstructure Development and Dielectric Characterization of Forsterite-Based Ceramics from Silicone Resins and Oxide Fillers

      Enrico Bernardo, Laura Fiocco, Guinevere A. Giffin, Vito Di Noto and Paolo Colombo

      Article first published online: 9 APR 2014 | DOI: 10.1002/adem.201400125

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      Mixtures of silicones and nano-sized MgO easily yield forsterite ceramics starting from 800 °C. Undesirable phases are suppressed using additional oxides, such as TiO2. Nano-TiO2 promotes the formation of Ti-doped forsterite, micro-TiO2 leads to forsterite/rutile composites, both featuring interesting dielectric characteristics (low dielectric constant, high quality factor, shown in the figure), despite the residual porosity.

    3. Intense Pulsed Light Sintering of Electrodeposited CdS Thin Films

      Ruvini Dharmadasa, I.M. Dharmadasa and Thad Druffel

      Article first published online: 8 APR 2014 | DOI: 10.1002/adem.201400008

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      Intense pulsed light (IPL) has been used to process cadmium sulfide (CdS) thin films, an important material in thin film solar cells. Pulses of incoherent light are absorbed by the material, leading to localized heating and sintering. This atmospheric processing technique resulted in significant improvement to the CdS crystallinity with processing times <2 mins.

  4. Reviews

    1. Additive Manufacturing of Ceramic-Based Materials

      Nahum Travitzky, Alexander Bonet, Benjamin Dermeik, Tobias Fey, Ina Filbert-Demut, Lorenz Schlier, Tobias Schlordt and Peter Greil

      Article first published online: 8 APR 2014 | DOI: 10.1002/adem.201400097

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      Main emphasis of this review is laid on the additive manufacturing of ceramic-based composites. Fabrication of ceramic components via three-dimensional printing, selective laser curing, three-dimensional extrusion freeforming, stereolithography, and laminated object manufacturing clearly demonstrates the high potential for materials science adaptation to additive manufacturing. The studies reviewed in this article will add the scientific base and extend the knowledge for designing and processing of novel advanced ceramic-based materials with complex geometry (see e.g.: SiSiC macrocellular functionally graded structures) and thus, will stimulate new fields of their applications.

  5. Editorials

    1. Achievements in Advanced Ceramics and Coating Processing

      Eugene Medvedovski and Nahum Travitzky

      Article first published online: 7 APR 2014 | DOI: 10.1002/adem.201400130

  6. Full Papers

    1. Field-Assisted Powder Synthesis and Consolidation of Fe–Ti–C Metal–Ceramic Composites

      Marya S. Yurlova, Aleksander N. Novoselov, Yen-Shan Lin, Olga N. Sizonenko, Evgeny G. Grigoryev, Oleg L. Khasanov and Eugene A. Olevsky

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201400105

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      Fe, Ti powders, and their mixtures are subjected to electric discharges in a hydrocarbon liquid. The obtained powder mixtures are consolidated by spark plasma sintering. The developed novel technological route uses electromagnetic field assistance at both powder synthesis and consolidation stages.

    2. Structure of Zirconium Alloy Powder Coatings Processed by High Voltage Electric Discharge Consolidation

      Evgeny G. Grigoryev, Lyuba Yu. Lebedeva, Oleg L. Khasanov and Eugene A. Olevsky

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201400106

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      Zirconium alloy powders (Zr + 1% Nb) of spherical and flake forms have been consolidated by high voltage electric discharge processing. The consolidation enabled the fabrication of coatings on ceramic and metallic substrates as well as of freestanding powder components.

    3. Behaviors of Ferromagnetic Shape Memory Alloy Ni–Mn–Ga Under Incomplete Magneto-Mechanical Loading–Unloading Cycles

      Rasoul Amrollahipour, Mahmoud Kadkhodaei and Parviz Kameli

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201400010

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      The behaviors of Ni–Mn–Ga under complete and incomplete magneto-mechanical loading/unloading cycles are studied. For elastic interruptions during loading/unloading, strain hardening is seen. If inelastic response is induced due to partial loading/unloading, return point memory effect appears during the subsequent unloading/loading.

  7. Communication

    1. Magneto-Acoustic Mixing Technology: A Novel Method of Processing Metal-Matrix Nanocomposites

      Hunter B. Henderson, Orlando Rios, Zachary L. Bryan, Cody P. K. Heitman, Gerard M. Ludtka, Gail Mackiewicz-Ludtka, Alexander M. Melin and Michele V. Manuel

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201300534

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      Magneto-acoustic mixing technology is evaluated as a method for manufacturing metal-matrix nanocomposites. This technology relies on the interaction of two magnetic fields to produce high-intensity acoustic waves suitable for melt processing of liquid metals, inducing sonic cavitation and dispersing nanoparticles. Considerations for alignment of particles in the system are also considered.

  8. Full Papers

    1. Microstructural Characterization and High-Temperature Mechanical Behavior of Cast Mg–4Zn–xSi Alloys

      Reza Alizadeh and Reza Mahmudi

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201400037

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      Mechanical properties of Mg–4Zn–xSi alloys are evaluated by the shear punch test method. The size and volume fraction of Mg2Si particles increase with increasing Si content. The Mg2Si particles are broken and dispersed as blocky particles in the Mg matrix after high temperature deformation, resulting in reduced ductility of the material.

    2. Colloidal Processing and Yield Stress Modeling Towards Dry Pressed Green Bodies for Transparent Polycrystalline Alumina

      Michael Stuer and Paul Bowen

      Article first published online: 2 APR 2014 | DOI: 10.1002/adem.201400099

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      That Mg and Y dopants are used to control alumina microstructures is well known but they have an adverse effect on suspension rheology. The dopants interact with the dispersant polyacrylic acid (PAA) and are-co-adsorbed via complexation with the PAA. This coupled with interparticle force and rheological modeling clarifies the rheolgical behavior.

    3. Polymeric Smart Coating Strategy for Titanium Implants

      Ida Berts, Dmitri Ossipov, Giovanna Fragneto, Andreas Frisk and Adrian R. Rennie

      Article first published online: 1 APR 2014 | DOI: 10.1002/adem.201400009

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      Titanium implants are improved when the interface provides local delivery of bone growth protein. Quartz crystal microbalance and neutron reflectivity measurements are used to determine the structure of a modified hyaluronan hydrogel coating and of adsorbed protein. The bound protein could be released when calcium ions were added to the solution.

  9. Reviews

    1. Macroporous Ceramics by Gelation–Freezing Route Using Gelatin

      Manabu Fukushima, Yu-ichi Yoshizawa and Tatsuki Ohji

      Article first published online: 31 MAR 2014 | DOI: 10.1002/adem.201400067

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      This paper reviews a gelation–freezing method to create nearly honeycomb shaped pore channels and the engineering applications of obtained macrocellular monoliths. Depending on freezing conditions carefully selected, cell size, wall thickness, number of cells, and cell interconnection can be modulated. Fabrication methods proposed are simple, economical, and versatile to produce macroporous ceramic monoliths.

  10. Full Papers

    1. Phase Transformation in Laser-Induced Micro-Explosion in Olivine (Fe,Mg)2SiO4

      Ričardas Buividas, Gediminas Gervinskas, Anton Tadich, Bruce C. C. Cowie, Vygantas Mizeikis, Arturas Vailionis, Dominique de Ligny, Eugene G. Gamaly, Andrei V. Rode and Saulius Juodkazis

      Article first published online: 31 MAR 2014 | DOI: 10.1002/adem.201400091

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      Near edge X-ray absorption fine structure spectra from laser-affected olivine show that micro-explosion generated by a femtosecond pulse produces change of iron valence state. This result indicates that spatial separation between ions of different mass occurs in hot, highly excited olivine. This mechanism presents a pathway toward new nano-materials.

  11. Review

    1. Ceramic Fibers Based on SiC and SiCN Systems: Current Research, Development, and Commercial Status

      Octavio Flores, Rajendra K. Bordia, Daisy Nestler, Walter Krenkel and Günter Motz

      Article first published online: 31 MAR 2014 | DOI: 10.1002/adem.201400069

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      Non-oxide ceramic fibers are key components for the reinforcement of lightweight thermostructural materials. This paper reviews the evolution of processing, microstructure and physical properties of commercially available CVD SiC fibers and three generations of polymers derived ceramic (PDC) SiC fibers over the past fifty years. Additionally discussion is focused on the recent advances in research and development related to ceramic fibers from SiC and SiCN systems.

  12. Full Papers

    1. Letting Corrosion Work for You: Novel Pathways to Additive Manufacturing and Nanomaterial Synthesis Using Electrochemically-Driven Powder Consolidation

      Andrew C. Johannes, Joseph C. Farmer, Luke N. Brewer and Sebastian Osswald

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201300562

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      Electrochemically-driven powder consolidation is a novel additive manufacturing technique that utilizes naturally occurring electrochemical potentials to consolidate metal and non-metal powders to rigid bodies and complex shapes. It also offers pathways for the bulk synthesis of new nanomaterials, metal foams, and advanced composites.

    2. Pulse Electrosynthesis of MnO2 Electrodes for Supercapacitors

      Yisong Su and Igor Zhitomirsky

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201400077

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      MnO2 electrodes for supercapacitors are prepared by cathodic pulse electrosynthesis, which allows impregnation of Ni plaque current collectors, designed for high power applications. The electrodes show high capacitance and high power-energy characteristics at high materials loadings.

  13. Reviews

    1. Microstructure and Properties of Carbon Fiber Reinforced SiC Matrix Composites Containing Ti3SiC2

      Xiaomeng Fan and Xiaowei Yin

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201400081

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      The tribological behavior of C/C-SiC and ablation resistance of C/SiC are improved by introducing Ti3SiC2, revealing that the introduction of MAX phases into ceramic matrix composites is an effective way to improve their performance and extend their application fields.

    2. Shaping of Dense Advanced Ceramics and Coatings by Gelation of Polysaccharides

      María Isabel Nieto, Isabel Santacruz and Rodrigo Moreno

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201400076

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      Illustration of the gel-dipping process, showing the variation of viscosity on cooling of Al2O3–ZrO2 suspensions prepared to a solids loading of 30 wt% and a relative ratio of 95/5 v/v, respectively using carrageenan (0.8 wt% referred to the solids loading), and the microstructure of the obtained coating sintered at 1550 °C/2 h.

  14. Communications

    1. Mechanical Properties of Hot Isostatically Pressed Li0.35La0.55TiO3

      Christopher Cooper, Anthony C. Sutorik, Jared Wright, E. Arthur Luoto III, Gary Gilde and Jeff Wolfenstine

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201400071

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      The mechanical properties of polycrystalline Li0.35La0.55TiO3 (LLTO) are investigated after sintering followed by hot isostatic pressing (HIP). The elastic modulus (223 GPa), hardness (Knoop hardness 7.2 GPa), and flexure strength (252 MPa) values for HIP LLTO are in general higher than those for other solid Li-ion conductors thus, making it an excellent choice as a Li-ion conducting solid electrolyte based on mechanical properties.

  15. Communication

    1. Functionally Graded Alloys Obtained by Additive Manufacturing

      Thomas Niendorf, Stefan Leuders, Andre Riemer, Florian Brenne, Thomas Tröster, Hans Albert Richard and Dieter Schwarze

      Article first published online: 28 MAR 2014 | DOI: 10.1002/adem.201300579

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      In the current study, selective laser melting is employed for direct manufacturing of functionally graded materials. An appropriate set of processing parameters allowing for direct microstructure manipulation of stainless steel is presented. Thorough analyses reveal a steep microstructural gradient resulting in distinct local mechanical properties. The process introduced will further give raise to the rapidly evolving field of additive manufacturing.

  16. Reviews

    1. Biopolymer-Based Gel Casting of Ferroelectric Ceramics

      Kevin P. Plucknett and Cameron D. Munro

      Article first published online: 27 MAR 2014 | DOI: 10.1002/adem.201400084

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      Aqueous gel casting of ferroelectric ceramics is investigated, using agar as a gelling aid. Combining high-solids content BaTiO3 suspensions (55 vol%), with concentrated agar solutions (up to 8 wt%), allows casting of components with high green densities (and final agar concentrations up to 1 wt% of the solids loading), which can be subsequently green-machined. Fine scale features (≈300 μm thick), with high aspect ratios (up to 13:1), are successfully fabricated.

    2. Cellulose-Based Biotemplated Silica Structuring

      Daniel Van Opdenbosch and Cordt Zollfrank

      Article first published online: 27 MAR 2014 | DOI: 10.1002/adem.201400085

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      Advances in the field of ceramic biotemplating based on cellulose templates are discussed. Particular emphasis is given to templating of silica on the nanometer scale. Principles that are employed by nature can be adapted by man to yield hitherto unattainable detailed and hierarchically structured materials.

    3. Processing and Characterization of Aluminum Nitride Ceramics for High Thermal Conductivity

      Hyun Min Lee, Kamala Bharathi and Do Kyung Kim

      Article first published online: 27 MAR 2014 | DOI: 10.1002/adem.201400078

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      The effects of sintering additives, microstructure, and morphology of second phase on the thermal conductivity of aluminum nitride ceramics (AlN) are discussed. The morphology of second phase in AlN ceramics could be controlled by changing the cooling rate. With the CaF2 addition, the formation of second phase can be suppressed and high thermal conductivity is achieved.

  17. Full Papers

    1. Outdoor Operational Stability of Indium-Free Flexible Polymer Solar Modules Over 1 Year Studied in India, Holland, and Denmark

      Dechan Angmo, Paul M. Sommeling, Ritu Gupta, Markus Hösel, Suren A. Gevorgyan, Jan M. Kroon, Giridhar U. Kulkarni and Frederik C. Krebs

      Article first published online: 25 MAR 2014 | DOI: 10.1002/adem.201400002

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      The long-term (over 1 year) stability of indium-tin-oxide (ITO)-free polymer solar cell modules (up-to 100 cm2) in outdoor and under storage are investigated in three different countries. Degradation is observed to be highly localized owing to encapsulation shortcomings. Simple improvement in the encapsulation method is carried out with dramatic improvement in the stability (shown in figure).

    2. Effect of SLM Parameters on Transformation Temperatures of Shape Memory Nickel Titanium Parts

      Sasan Dadbakhsh, Mathew Speirs, Jean-Pierre Kruth, Jan Schrooten, Jan Luyten and Jan Van Humbeeck

      Article first published online: 25 MAR 2014 | DOI: 10.1002/adem.201300558

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      Selective laser melting (SLM) of nickel titanium represents a promising future owing to SLM ability to manufacture complex shapes. This work presents original experimental data to successfully manufacture NiTi parts using the SLM process. It also describes a systematic study to illustrate the effect of different sets of SLM parameters on the transformation temperatures, mechanical behavior, microstructure, and shape memory response of the products.

    3. Mechanical Properties of Nanocrystalline and Ultrafine-Grained Nickel with Bimodal Microstructure

      Tao Qian, Ibrahim Karaman and Michael Marx

      Article first published online: 20 MAR 2014 | DOI: 10.1002/adem.201300570

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      Improving ductility while keeping the high toughness of nanocrystalline (NC) and ultrafine-grained (UFG) materials can be achieved by introducing a bimodal microstructure. The paper compares mechanical properties and fatigue resistance of bimodal nickel produced from NC pulse electrodeposited nickel and UFG severe plastic deformation nickel where NC/UFG nickel shows the best mechanical properties.

    4. Suppression of Void Formation in Si0.5Ge0.5 Alloy Nanowire during Ni Germanosilicidation

      Yida Li, Kavitha Buddharaju, Xin-Peng Wang, Sung-Joo Lee and Thiam-Leong Thong

      Article first published online: 20 MAR 2014 | DOI: 10.1002/adem.201300462

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      In the process of nickel reacting with silicon-germanium nanowires under high temperature (600 °C) to form nickel germanosilicide, voids begin to form due to the out-diffusion of germanium atoms toward the nickel source, and eventually leads to a break in the silicon-germanium nanowire.

    5. Stretchable Metallic Electrodes for Electroactive Polymer Actuators

      Florian Habrard, Jörg Patscheider and Gabor Kovacs

      Article first published online: 7 MAR 2014 | DOI: 10.1002/adem.201300569

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      Thin silver films are deposited by magnetron sputtering for use as electrodes in electroactive polymer actuators (EAPs). They can be biaxially stretched up to 13% in one direction without losing electrical conductivity. This is achieved by films with grain size <20 nm and open pore structure using high deposition pressures. Low pressures yield dense films, which crack already at 4% straining.

    6. Robust Technique Allowing the Manufacture of Superoleophobic (Omniphobic) Metallic Surfaces

      Anton Starostin, Viktor Valtsifer, Vladimir Strelnikov, Edward Bormashenko, Roman Grynyov, Yelena Bormashenko and Alexander Gladkikh

      Article first published online: 5 MAR 2014 | DOI: 10.1002/adem.201300561

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      Omniphobic metallic surfaces obtained with a robust process are reported. The surfaces demonstrate high apparent contact angles accompanied with a low contact angle hysteresis for a variety of liquids, including canola, castor, silicone oils, and crude petroleum oil. The superoleophobicity was achieved by fluorination of the nano-rough aluminum surfaces.

  18. Communications

    1. New Methods for Developing and Manufacturing Compliant Mechanisms Utilizing Bulk Metallic Glass

      Eric R. Homer, Matthew B. Harris, Shannon A. Zirbel, Joanna A. Kolodziejska, Henry Kozachkov, Brian P. Trease, John-Paul C. Borgonia, Gregory S. Agnes, Larry L. Howell and Douglas C. Hofmann

      Article first published online: 5 MAR 2014 | DOI: 10.1002/adem.201300566

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      Compliant mechanisms rely on the elastic bending of thin members to generate motion. In the paper by Homer, et al., bulk metallic glasses (BMGs) are shown to have an optimal combination of mechanical properties and processing ability, making them ideal for complex, low-cost compliant mechanisms.

    2. Composition and Mechanical Properties of a Protein/Silica Hybrid Material Forming the Micron-Thick Axial Filament in the Spicules of Marine Sponges

      Igor Zlotnikov, Admir Masic, Yannicke Dauphin, Peter Fratzl and Emil Zolotoyabko

      Article first published online: 5 MAR 2014 | DOI: 10.1002/adem.201300485

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      Nearly equal volume fractions of biosilica and proteins are found in the micron-thick axial filament of the anchor spicule of the marine sponge Monorhaphis chuni. Chemical composition and mechanical properties of this unique composite material are characterized by confocal Raman spectroscopy and by nanoindentation and nanoscale elastic modulus mapping, respectively.

  19. Full Papers

    1. The Banded Structure and Its Effects on the Transverse Elongation and Textures of Mo Bars

      Shan Wang, Chang Chen, Yanlin Jia and Mingpu Wang

      Article first published online: 5 MAR 2014 | DOI: 10.1002/adem.201300505

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      The transverse elongation of draw-forged pure Mo bars is improved by upsetting. After upsetting deformation, a 〈011〉 fiber texture evolves into 〈100〉 + 〈111〉 fiber textures. The formation of a 〈110〉 fiber or a 〈100〉 fiber can be explained by a cross-slip mechanism, and the formation of a 〈111〉 fiber can be explained by a microshear banding mechanism.

    2. Fatigue Life and Failure Characteristics of an Ultrafine-Grained Ti–6Al–4V Alloy Processed by ECAP and Extrusion

      Alexander V. Polyakov, Irina P. Semenova, Yi Huang, Ruslan Z. Valiev and Terence G. Langdon

      Article first published online: 27 FEB 2014 | DOI: 10.1002/adem.201300530

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      A Ti–6Al–4V alloy is processed using equal-channel angular pressing and extrusion to produce an ultrafine-grained (UFG) material with a grain size of 240 nm. Tensile testing shows increased tensile strength compared with the coarse-grained (CG) material. In fatigue testing, the UFG alloy has a longer fatigue life than the CG material.

    3. You have full text access to this OnlineOpen article
      High Temperature Behavior of Si3N4 and Yb2SiO5 Coated Carbon Fibers for Silicon-Nitride CMC

      Peter Pontiller and M. Willert-Porada

      Article first published online: 21 FEB 2014 | DOI: 10.1002/adem.201300443

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      Two different coatings are compared: reactive CVD-derived Si3N4 coatings to investigate C-fiber-matrix reactions and Yb-silicate coatings to reveal potential reactions with the Yb-silicate additive serving as sintering aid for Si3N4. A new ceramic phase – an Yb-carbido-nitiridosilicate, Yb2Si4CN6–is found as product of carbothermal reduction of the Yb-silicate. The carbothermal reduction occurs also with other RE-silicates, RE = Yb, Er, Y, Gd, and Sm while SiC is found as reaction product on carbon fibers coated with Si3N4. The role of Yb2Si4CN6 as reinforcement for Si3N4-CMC is discussed based on bond strength comparison of carbides (SiC), nitride silicates (SiAlON), and nitrides (Si3N4).

  20. Communication

    1. Manipulation of TiH2 Decomposition Kinetics for Two Steps Foaming Method

      Si-Yuan He, Zong-Ren Jiang, Ge Dai, Yi Zhang and Xiao-Lu Gong

      Article first published online: 21 FEB 2014 | DOI: 10.1002/adem.201300535

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      Two Steps Foaming method is a promising alternative to prepare net-shaped aluminum foam and aluminum foam core sandwich. In this route, the pre-oxidized foaming agents are dispersed in aluminum melt and the mixtures are quenched to obtain a foamable precursor. The partial decomposition of TiH2 during dispersion makes this method complicated. This study theoretically analyzes the quantitative relationship between the process parameters and the hydrogen evolution kinetics during the two process stages. The process parameters are optimized and verified experimentally.

  21. Communications

    1. Highly Reliable Carbon Nanotube-Based Composite Fibers Cross-Linked by a 3D Polymer Network

      Gengzhi Sun, Lianxi Zheng, Zhaoyao Zhan, Chunbo Jiang, Reinack V. Hansen, Yengpeng Khor and John H. L. Pang

      Article first published online: 21 FEB 2014 | DOI: 10.1002/adem.201300436

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      For practical applications, carbon nanotubes (CNTs) have to be assembled into macroscopic architectures, and CNT fiber presents itself as a promising candidate. However, CNTs inside a CNT fiber slide considerably during static and cyclic tensile tests, which is unfavorable for long-term performances. In this study, a second phase has been introduced into CNT fiber in order to enhance its reliability. The results show the composite fibers exhibit excellent stress-relaxation resistance, effective load transfer, and thus an improved mechanical reliability.

  22. Full Papers

    1. Influence of Sulfur on the Recrystallization and {100}〈001〉 Cube Texture Formation in Fe48%Ni Alloys Tapes

      Yanick Ateba Betanda, Anne-Laure Helbert, François Brisset, Mickael Wehbi, Marie-Hélène Mathon, Thierry Waeckerlé and Thierry Baudin

      Article first published online: 20 FEB 2014 | DOI: 10.1002/adem.201300419

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      The addition of sulfur in the Fe48%Ni alloys favors the formation of Cube texture. In the Fe48%Ni alloys tapes, the fraction of Cube grains {100}〈001〉 increases in the recrystallized states when the sulfur content increases (a–e). In the deformed states, the stored energy of the main cold-rolled components that are S {132}〈6–43〉, C {112}〈11–1〉, and B {110}〈1–12〉, remains quasi constant with sulfur content (f). Thus, the stored energy difference between the Cube and other orientations (ΔECube/Other) increases when sulfur is added (g). This stored energy difference is the driving force of the Cube grains formation. Therefore, the increase of ΔEOther/Cube promotes the Cube grains formation and growth during the recrystallization.

    2. Contribution to the Laser Welding of Wrought and Spray-Compacted Aluminum Alloys and the Impact of the Alloy Composition on the Welding Microstructure

      Thomas Gietzelt, Lutz Eichhorn, Torsten Wunsch, Uta Gerhards, Thomas Przeorski, Holger Weiss and Roland Dittmeyer

      Article first published online: 18 FEB 2014 | DOI: 10.1002/adem.201300497

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      CW-laser welding experiments are performed at different power, focal position and velocities using two optical fibers. As materials, AlMg3 and spray-compacted hypereutectic aluminum alloys with silicon contents of 17–35% are used. For AlMg3, shrink pores were observed for a broad range of parameters whereas defect-free weld seams with specular precipitations are observed for the hypereutectic aluminum alloys.

    3. Grain Boundary Plane Distributions in a Hot Rolled 5A06 Aluminum Alloy

      Xiaokun Yuan, Kunyuan Gao, Gregory S. Rohrer and Xiaoying Fang

      Article first published online: 18 FEB 2014 | DOI: 10.1002/adem.201300458

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      By virtue of five-parameter analysis method, the orientations of grain boundary planes are proved to be textured in a hot rolled 5A06 aluminum alloy. Boundaries situated at the center and surface positions of the specimen favor the {111} and {110} orientations respectively, and such anisotropic distribution occurs at all misorientation angles.

  23. Reviews

    1. Thermal Management Material: Graphite

      Michio Inagaki, Yutaka Kaburagi and Yoshihiro Hishiyama

      Article first published online: 12 FEB 2014 | DOI: 10.1002/adem.201300418

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      Graphite membranes with high thermal conductivity in parallel for heat dissipation and with low conductivity in perpendicular for heat insulation, in addition to graphite foams as container of phase change materials for heat energy storage, are reviewed, referring to their preparation. Thermal conductivity of graphitic materials is less sensitive for structural defects, suggesting practical possibility for thermal management.

  24. Full Papers

    1. Anomalous Behavior of Load-Dependent Friction on Ultra-Nanocrystalline Diamond Film

      Ramadoss Radhika, Niranjan Kumar, Sitaram Dash, Ashok K. Tyagi and I-Nan Lin

      Article first published online: 12 FEB 2014 | DOI: 10.1002/adem.201300515

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      Load-dependent anomalous behavior of friction coefficient in ultra-nanocrystalline diamond (UNCD) film is investigated while sliding against SiC ball. At low and high loads, the magnitude of friction coefficient is high. However, at intermediate loads, ultra-low friction coefficient 0.002 is measured. Load-dependent friction behavior is explained by chemical nature of sliding surfaces and development of transferlayer.

    2. Microstructural Analysis of Electron Beam Cladded Surface Layers Using Co- and Fe-Enriched Additives

      Anne Jung, Rolf Zenker, Joachim Lerche and Kristina Lerche

      Article first published online: 7 FEB 2014 | DOI: 10.1002/adem.201300507

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      The paper focuses on the microstructural investigation of wear protective surface layers on stainless steels X2CrNiMoN22-5-3 and X6CrNiMoTi17-12-2 generated by means of electron beam cladding using Fe- and Co-base additives. The influence of a multiple layer cladding as well as the amount of affected base material is discussed. The layer composition is investigated by means of EPMA and EXD analysis. The generated phases are identified by X-ray analysis. Hardness-depth profiles prove the influence of microstructure and base material content on hardness. With increasing number of cladding layers the influence of base material on microstructure and hardness range is decreasing.

    3. Powder Semi-Solid Casting Technology for Preparation of High Chromium Cast Iron Alloy

      Jianjun He and Xianze Li

      Article first published online: 7 FEB 2014 | DOI: 10.1002/adem.201300510

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      A new preparation technology, termed powder semi-solid (PSS) casting, has been developed for the preparation of fine-grained alloys. In this process, certain amount of alloy powder, which has the same composition as the melt, is added into the melt and then immediately stirred. The M7C3 carbide phases in the as-cast alloy are fine batten-like or in equiaxed shape and their ratio of length to radial reduces. The eutectic colonies and α-Fe are refined greatly comparing with that of the conventionally cast alloys.

    4. Electrical and Piezoelectric Behavior of Polyamide/PZT/CNT Multifunctional Nanocomposites

      Delphine Carponcin, Eric Dantras, Jany Dandurand, Gwenaëlle Aridon, Franck Levallois, Laurent Cadiergues and Colette Lacabanne

      Article first published online: 6 FEB 2014 | DOI: 10.1002/adem.201300519

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      Three-phase polyamide 11 (PA 11)/lead zirconate titanate (PZT)/carbon nanotubes (CNT) composites are elaborated by extrusion. The dielectric permittivity of PA 11/PZT composites is greatly improved with the addition of only 0.2% in volume of carbon nanotubes. Both the increase of the poling field efficiency and the variation of the piezoelectric coefficient due to the presence of carbon nanotubes are also shown.

    5. Geometry-Induced Mechanical Properties of Carbon Nanotube Foams

      Ludovica Lattanzi, Luigi De Nardo, Jordan R. Raney and Chiara Daraio

      Article first published online: 6 FEB 2014 | DOI: 10.1002/adem.201300524

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      Micro-patterned VACNT structures are grown using different 2D lattices as growth templates. Quasi-static compressive tests show that the structural architecture plays a fundamental role on the energy absorption capability, maximum stress, and strain recovery. The study confirms the possibility of designing lighter CNT structures able to maintain desirable mechanical characteristics by tailoring the microstructural architecture.

    6. The Project SupraMetall: Towards Commercial Fabrication of High-Temperature Superconducting Tapes

      Marco Witte, Günter Gottstein, Nicole de Boer, Stefan Gilges, Jutta Klöwer, Michael Bäcker, Oliver Brunkahl, Brygida Wojtyniak, Werner Mader, Matthias Svete, Sven-Martin Hühne, Sabine Lepper, Regina Böhm and Manuela Schebera

      Article first published online: 6 FEB 2014 | DOI: 10.1002/adem.201300415

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      The aim of the project SupraMetall is to enable the large scale production of hightemperature superconducting tapes. This is a report of the recent achievements in the production of Cube textured metal substrates and the coating techniques of the buffer and superconductive layers. The final tapes reached critical current densities of 120 A/cm-width.

    7. Martensitic Phase Transformation and Deformation Behavior of Fe–Mn–C–Al Twinning-Induced Plasticity Steel during High-Pressure Torsion

      Kun Yan, Dhriti Bhattacharyya, Qi Lian, Saurabh Kabra, Megumi Kawasaki, David G. Carr, Mark D. Callaghan, Maxim Avdeev, Huijun Li, Yanbo Wang, Xiaozhou Liao, Terence G. Langdon, Klaus-Dieter Liss and Rian J. Dippenaar

      Article first published online: 5 FEB 2014 | DOI: 10.1002/adem.201300488

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      High pressure torsion of TWIP steel shows the formation of an HCP Martensite phase, whose volume fraction first increases, then decreases with increasing strain, as shown by local synchrotron diffraction at various points along the radius of the sample, and neutron diffraction on samples with increasing number of turns. Local texture analysis shows the correlation between position and predominant deformation mechanism.

  25. Communication

    1. Micro Mirror Polymer Composite Offers Mechanically Switchable Light Transmittance

      Aline C. C. Rotzetter, Roland Fuhrer, Robert N. Grass, Christoph M. Schumacher, Philipp R. Stoessel and Wendelin J. Stark

      Article first published online: 28 JAN 2014 | DOI: 10.1002/adem.201300478

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      Elastic silicone composites with mechanically switchable transparency are generated by incorporating micron-sized aluminum platelets into a highly flexible silicone. Physisorbing Fe3O4 nanoparticles onto the platelets surface allow magnetic pre-alignment during the polymer curing. One-dimensional or two-dimensional stretching of the resulting silicone composites permits orientation of the incorporated flakes and alters light transmittance of the polymer coating.

  26. Full Papers

    1. Fabrication and Deformation of Metallic Glass Micro-Lattices

      Jan Rys, Lorenzo Valdevit, Tobias A. Schaedler, Alan J. Jacobsen, William B. Carter and Julia R. Greer

      Article first published online: 28 JAN 2014 | DOI: 10.1002/adem.201300454

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      This work presents the fabrication, characterization and properties of hollow metallic glass nickel-phosphorous microlattices. We discovered that at wall thicknesses below ≈150nm the mechanical properties can no longer be calculated by classical models, with strengths nearly an order of magnitude higher than predicted. This is caused by a shift in deformation mechanism from post-elastic catastrophic failure in thick-walled structures to localized plastic deformability, which emerges as a result of brittle-to-ductile transition in nano-sized metallic glasses. These findings suggest a viable and economic route to design and fabricate high-strength, lightweight structural materials by combining structural effects with material size effects.

  27. Communication

    1. Analytical Model of the Unbending Behavior of Corrugated Reinforcements

      Mark Fraser, Hatem Zurob, Peidong Wu and Olivier Bouaziz

      Article first published online: 27 JAN 2014 | DOI: 10.1002/adem.201300525

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      In this contribution, the tensile behavior of an isolated corrugated sheet is analyzed. A simple analytical model is developed to describe the unbending of the corrugation and the stretching of the sheet as a function of the initial geometric and material parameters. The model predictions are in good agreement with experimental observations for corrugated sheets of IF steel.

  28. Full Papers

    1. Grain Boundary Phenomena in an Ultrafine-Grained Al–Zn Alloy with Improved Mechanical Behavior for Micro-Devices

      Nguyen Q. Chinh, Ruslan Z. Valiev, Xavier Sauvage, Gábor Varga, Károly Havancsák, Megumi Kawasaki, Boris B. Straumal and Terence G. Langdon

      Article first published online: 27 JAN 2014 | DOI: 10.1002/adem.201300450

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      High-pressure torsion is used to produce an ultrafine-grained structure in an Al–30% Zn alloy and the mechanical behavior is investigated using various techniques. We show that Zn-rich layers form at the Al/Al grain boundaries, which enhance the role of grain boundary sliding and produce stable deformation, even at the micro-scale, without the strain avalanches, which characterize micro-sized coarse-grained crystals.

    2. Synthesis and Tribological Behaviors of Epoxy/Phosphazene-Microspheres Coatings under Dry Sliding Condition

      Zhengping Zhao and Jianbing Ji

      Article first published online: 22 JAN 2014 | DOI: 10.1002/adem.201300491

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      One step to synthesize a kind of organic-inorganic hybrid microspheres via precipitation polymerization and filled epoxy matrix to prepare composite coatings to study the thermal and friction properties and to discuss the modified mechanisms. The microspheres have average particle diameter of 500 nm and significant improvement effect on wear resistance.

    3. Evaluating a New Core-Sheath Procedure for Processing Hard Metals by Equal-Channel Angular Pressing

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

      Article first published online: 22 JAN 2014 | DOI: 10.1002/adem.201300474

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      A new billet design is introduced, which has been used successfully to process NiTi as a hard-to-deform material by ECAP through two passes at room temperature. In this procedure, the hard-to-deform material is inserted as a core within an Fe sheath to give a core–sheath billet. The present investigation is initiated to evaluate the deformation behavior occurring within core–sheath billets of three different materials processed by ECAP. The results reveal the presence of a zone of lower strain along the lower part of the core.

    4. Aluminum–Iodoform Composite Reactive Material

      Ani Abraham, Shasha Zhang, Yasmine Aly, Mirko Schoenitz and Edward L. Dreizin

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300400

      Thumbnail image of graphical abstract

      Al[BOND]CHI3 composites are prepared with iodine concentration of 20 wt% using cryo-milling. Iodine is released upon heating in stages with the main weight loss near the Al melting. The materials oxidize in two main steps. The ignition temperatures of the prepared materials are lower compared to similar Al · I2 composite prepared using cryo-milling.

    5. Rapid Formation of a Monolayer of Oriented Hard-Magnetic Strontium Hexaferrite Nanoparticles on a Solid Substrate

      Sergey E. Kushnir, Dmitry S. Koshkodaev, Pavel E. Kazin, Dmitry M. Zuev, Dmitry D. Zaytsev and Martin Jansen

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300448

      Thumbnail image of graphical abstract

      Monolayers of oriented platelet strontium hexaferrite nanoparticles form readily on a glass surface while immersing the substrate in the charge stabilized colloidal solution of the particles. The films show almost rectangular magnetization hysteresis loops typical for strongly textured hard-magnetic materials.

    6. Effect of Defects Induced by 12C+ Ion Irradiation on the Fluorination of Pyrolytic Carbon Coating in Flinak Salt

      Shanglei Feng, Li Li, Xinmei Yang, Xingtai Zhou, Shuo Bai and Tsun Kong Sham

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300479

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      Pyrolytic carbon (PyC) coating is used as a candidate protector of unclear graphite to against the impregnation of molten Flinak salt in molten salt reactor. This study primarily investigates the effect of defects induced by 12C+ ion irradiation on the fluorination of PyC coating in Flinak salt. Results show evidence for the formation of C[BOND]F bond, and the defects facilitate the fluorination of PyC coating in Flinak salt.

    7. Sustained Percolation in Stretched Silver Nanowire Networks for Stretchable Inter-Connection Applications

      Jae Sung Park, Mohamad Rezaei and Woo Soo Kim

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300483

      Thumbnail image of graphical abstract

      Synergized effects of stress-relieved horseshoe pattern and flexibility of silver nanowire (AgNW) network enable the printed circuit board (PCB) to have sustained percolation in stretched AgNW network. A stretchable PCB inter-connection is allowed by highly flexible AgNW electrode on polydopamine-treated silicone rubber substrate. And optimized meander structure keeps AgNW's percolation for maintaining high conductivity during stretching demonstration.

    8. Fracture Toughness Healing in Epoxy Containing Both Epoxy and Amine Loaded Capsules

      Sam Neuser, Philipp W. Chen, André. R. Studart and Véronique Michaud

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300422

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      Fracture surface of an epoxy sample containing a two component microcapsule system based on a common epoxy and amine chemistry after a first break, followed by healing and then fractured again. A rough layer of the in situ formed adhesive film is observed in the present autonomously healed sample. The curing agent microcapsules were produced based on a novel microfluidic encapsulation technique and using this new self-healing system, successful mending of fractured samples is observed also in fully cured epoxy matrix with healing efficiencies of up to 100% of the virgin fracture toughness.

  29. Communication

    1. Microstructure and Tribological Properties of the Ti3AlC2 Coating on A Ti–46Al–2Cr–2Nb Alloy

      Jun Cheng, Jiqiang Ma, Licai Fu, Shengyu Zhu, Zhuhui Qiao, Jun Yang and Weimin Liu

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300504

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      This article presents a new solution for the lubrication and wear problem of TiAl alloy in vacuum by coating Ti3AlC2 layer. Ti3AlC2 coating and Ti-46Al-2Cr-2Nb alloy substrate are simultaneously consolidated by hot-pressed approach. The coating demonstrates superior self-lubricity, CoF of 0.2 and negligible wear, in the vacuum of 2.0 × 104 Pa. A transition layer is formed in the interface, resulting in very strong coating adhesion.

    2. Amorphous Nitrogen Doped Carbon Films: A Novel Corrosion Resistant Coating Material

      Miao Zhu, Xinming Li, Zexia Zhang, Pengzhan Sun, Xiaobei Zang, Kunlin Wang, Minlin Zhong, Dehai Wu and Hongwei Zhu

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300408

      Thumbnail image of graphical abstract

      The challenge in developing a protection barrier from corrosion is to develop an economical yet efficient method for the coating material. Graphene has been deemed to be an ideal coating material for anti-corrosion, yet its long-term performance is disappointing due to galvanic corrosion. In an effort to address issues associated with graphene materials, we have developed an amorphous nitrogen doped carbon (a-CN) film material exhibiting remarkable anti-corrosion properties. The anti-corrosion performance of this material appears to be superior to graphene because of its strong ion transportation resistance.

  30. Full Papers

    1. Foldable Textile Electronic Devices Using All-Organic Conductive Fibers

      Hiroaki Miura, Yasuhiro Fukuyama, Takashi Sunda, Bangjia Lin, Jian Zhou, Junko Takizawa, Akio Ohmori and Mutsumi Kimura

      Article first published online: 20 JAN 2014 | DOI: 10.1002/adem.201300461

      Thumbnail image of graphical abstract

      Scalable conductive multifilament of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrene sulfonate) and poly(vinyl alcohol) is fabricated through wet-spinning, and the resulted blended fibers work as electromechanical actuators and flexible electrodes to detect human heartbeats.

  31. Communication

    1. Effect of Inclusion Agglomeration and Percolation on the Dynamic Stiffness of Composite Materials with Coated Spherical Inclusions

      Samuel T. Andermatt and Andrei A. Gusev

      Article first published online: 27 DEC 2013 | DOI: 10.1002/adem.201300459

      Thumbnail image of graphical abstract

      Using a combination of cross-validated analytical and numerical tools, we investigate the effect of inclusion agglomeration on the dynamic stiffness of composite materials with coated inclusions. Our results indicate that such composite materials with percolating and agglomerating microstructures can exhibit appealing increases in both stiffness and loss moduli.

  32. Full Papers

    1. Enhancing the Mechanical Properties of AE42 Magnesium Alloy through Friction Stir Processing

      Harpreet Singh Arora, Harpreet Singh Grewal, Harpreet Singh, Brij Kumar Dhindaw and Sundeep Mukherjee

      Article first published online: 27 DEC 2013 | DOI: 10.1002/adem.201300440

      Thumbnail image of graphical abstract

      The influence of Friction stir processing on the mechanical properties of a Mg alloy was investigated. Tensile testing revealed significantly higher modulus and yield strength for the friction stir processed specimen with some improvement in ductility. The fractured surface of the base metal showed ridges, grooves and cracks indicating brittle failure. In contrast, the fractured surface of friction stir processed specimen demonstrated ductile failure.

    2. Investigation of the Thin-Film Phase Diagram of the Cr–Ni–Re System by High-Throughput Experimentation

      Amin Janghorban, Janine Pfetzing-Micklich, Jan Frenzel and Alfred Ludwig

      Article first published online: 27 DEC 2013 | DOI: 10.1002/adem.201300430

      Thumbnail image of graphical abstract

      The complete Cr–Ni–Re system is investigated using combinatorial fabrication combined with high-throughput characterization techniques in order to establish its thin film phase diagram at 1100 °C. Results show that the obtained phase diagram is well comparable to the bulk phase diagram and that the combinatorial thin film phase diagram approach is promising for systems with expensive or high melting point constituents.

    3. Strain Sensing Behavior and Its Mechanisms of Electrically Conductive PPy-Coated Fabric

      Junpu Wang, Pu Xue, Xiaoming Tao and Tongxi Yu

      Article first published online: 21 DEC 2013 | DOI: 10.1002/adem.201300407

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      This paper studies the strain sensing behavior and its mechanisms of polypyrrole (PPy)-coated Lycra/Nylon knitted fabric. The electrical resistance varies differently in yarn slippage, change of contacted fibers, bending of yarns, as well as elongation of yarns, and the micro-cracks of the coating surface during fiber extension contributes most to the resistance variation of the fabric among the four deformation stages.

  33. Communication

    1. Duplex Surface Treatment – Physical Vapor Deposition (PVD) and Subsequent Electron Beam Hardening (EBH)

      Gundis Grumbt, Rolf Zenker, Horst Biermann, Kai Weigel, Klaus Bewilogua and Günter Bräuer

      Article first published online: 19 DEC 2013 | DOI: 10.1002/adem.201300411

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      Subsequent EBH improves the load-supporting capacity of PVD-coated steels. The influence of the chemical composition and layer thickness of Ti1−xAlxN coatings on the results of EBH was investigated. Increasing Al contents, along with increasing layer thicknesses improve the heat input during EBH. It is possible to harden the steel through the PVD layer without negative influences on the metastable coatings.

    2. Effect of Fiber's Interfaces Cohesive Strength in Unidirectional Fibrous Structural Material on SIF and Fracture Energy

      Alexandra V. Borovik and Valery G. Borovik

      Article first published online: 19 DEC 2013 | DOI: 10.1002/adem.201300449

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      This paper presents the study of the effect of inelastic shear stress at the interface between the fibers on the SIF and energy absorbed at the initial stages of the fracture of the material with unidirectional fibrous structure. The dependence between the energy absorbed by the deformation of the fiber with a crack, and the cohesive strength of the interface has a domed form with a well-defined maximum.

    3. First Direct In Situ Observation of Grain Boundary Sliding in Ultrafine Grained Noble Metal

      Kejing Yang, Hans-Jörg Fecht and Yulia Ivanisenko

      Article first published online: 19 DEC 2013 | DOI: 10.1002/adem.201300413

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      The unambiguous experimental evidence that grain boundary sliding and shear banding are important mechanisms of plasticity in ultrafine-grained Pd with an average grain size of 134 nm was obtained using in situ scanning electron microscopy combined with orientation imaging techniques.

    4. Microstructure Characterization and Mechanical Properties of In Situ Synthesized Ti2AlN/Ti48Al2Cr2Nb Composites

      Yiwen Liu, Rui Hu, Tiebang Zhang, Hongchao Kou and Jinshan Li

      Article first published online: 18 DEC 2013 | DOI: 10.1002/adem.201300417

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      With moderate content Ti2AlN (3 vol%), Ti2AlN/4822 composite prepared by in situ reactive arc-melting exhibits higher compression strength and better ductility than unreinforced 4822 alloy. The excellent properties are attributed to the introduction of Ti2AlN, which enhances the matrix, significantly refines the grain size, and decreases the dendritic segregation of the composites.

  34. Communications

    1. Dual-Growth-Factor-Releasing PCL Scaffolds for Chondrogenesis of Adipose-Tissue-Derived Mesenchymal Stem Cells

      Sung Mook Lim, Sung Hwan Jang, Se Heang Oh, Soon Hong Yuk, Gun Il Im and Jin Ho Lee

      Article first published online: 21 DEC 2009 | DOI: 10.1002/adem.200900153

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      Dual-growth-factor (TGF-β2/BMP-7)-immobilized PCL/Pluronic F127 porous scaffolds were fabricated using a modified melt-molding particulate-leaching method followed with the binding of heparin and growth factors onto the pore surfaces of the scaffolds. From the in vitro chondrogenesis study, it was observed that the dual TGF-β2/BMP-7-immobilized scaffold induced better chondrogenic differentiation than the single-growth-factor-immobilized scaffolds or control scaffold (without growth factor), probably owing to the synergistic effect of both growth factors.

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