Advanced Engineering Materials

Cover image for Vol. 17 Issue 6

Early View (Online Version of Record published before inclusion in an issue)

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  1. 1 - 100
  2. 101 - 122
  1. Full Papers

    1. Nanocrystalline Low-Refractive Magnesium Fluoride Films Deposited by Reactive Magnetron Sputtering: Optical and Structural Properties

      Stefan Mertin, Laurent Marot, Cosmin S. Sandu, Roland Steiner, Jean-Louis Scartezzini and Paul Muralt

      Article first published online: 2 JUL 2015 | DOI: 10.1002/adem.201500129

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      Synthesis and properties of novel nanocrystalline magnesium fluoride (MgF2) thin films. A novel reactive sputtering process for highly transparent MgF2 films is studied. These nanocrystalline films exhibit a very-low refractive index of 1.382 at 550 nm and a near-zero absorption in the whole solar spectral range. A quaternary film of this nanocrystalline MgF2 on glass reduces light reflection by 3%.

    2. Effects of Mg17Sr2 Phase on the Bio-Corrosion Behavior of Mg–Zr–Sr Alloys

      Yunfei Ding, Yuncang Li and Cuie Wen

      Article first published online: 2 JUL 2015 | DOI: 10.1002/adem.201500222

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      The Mg17Sr2 phase in Mg5ZrxSr (x ≤ 5 wt%) alloys plays a crucial role on their bio-corrosion behavior. The corrosion starts from the galvanic effects between the Mg17Sr2 phase and the Mg matrix and subsequently extends from the regions adjacent to the Mg17Sr2 phase gradually to the central Mg matrix.

    3. Versatile Self-Cleaning Coating Production Through Sol–Gel Chemistry

      A. C. Power, A. Barrett, J. Abubakar, L. J. Suarez, L. Ryan, D. Wencel, T. Sullivan and F. Regan

      Article first published online: 1 JUL 2015 | DOI: 10.1002/adem.201500112

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      This work describes the development of a self-cleaning coating using a nanoparticle coated super hydrophobic sol–gel. The material is flexible, transparent and robust, and suitable for application to optical windows or solar panels. The coating can be easily applied as a two-part solution by spraying.

    4. The Enhanced Shape Memory Effect and Mechanical Properties in Thermomechanically Processed Semi-Equiatomic NiTi Shape Memory Alloy

      A. Shamsolhodaei, A. Zarei-Hanzaki and H. R. Abedi

      Article first published online: 29 JUN 2015 | DOI: 10.1002/adem.201500252

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      The hot compression tests were carried out in a wide range of temperatures and strain rates. A significant influence on the critical transformation temperatures was realized. This could affect the martensite plates’ features and the fraction of retained austenite phase. In consequence the room temperature mechanical properties and shape memory response of the alloy were influenced. In an optimized specimen, the recovery ratio was increased from ≈30% to ≈80%.

  2. Communications

    1. Size Effects in the Mechanical Properties of Bulk Bicontinuous Ta/Cu Nanocomposites Made by Liquid Metal Dealloying

      Ian McCue, Stephen Ryan, Kevin Hemker, Xiandong Xu, Nan Li, Mingwei Chen and Jonah Erlebacher

      Article first published online: 29 JUN 2015 | DOI: 10.1002/adem.201500219

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      Extremely strong and ductile Cu/Ta bulk nanocomposites are fabricated by liquid metal dealloying. These materials exhibit a complex two-phase microstructure with a tunable length scale that allows for a significant increase in strength with decreasing feature size. Their yield behavior is consistent with a bulk manifestation of size effects previously associated only with nanofabricated materials.

  3. Full Papers

    1. A Flexible Encapsulation Structure for Ambient-Air Operation of Light-Emitting Electrochemical Cells

      A. Asadpoordarvish, A. Sandström and L. Edman

      Article first published online: 26 JUN 2015 | DOI: 10.1002/adem.201500245

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      We report the fabrication and ambient-air performance of flexible light-emitting electrochemical cells (LECs). A flexible LEC sandwiched between multilayer barriers, featuring a water and oxygen barrier property of ≈1 × 10−3 g/m2/day and ≈1 × 10−3 cm3/m2/bar/day respectively, and as attached together with UV-curable epoxy, performs on par with identical glass-encapsulated devices. Such a flexible LEC also remains functional after one year storage under ambient air.

    2. Stimulation by Pearl of Mineralization and Biocompatibility of PLA

      Jiamu Dai, Jingjing Bai, Junhong Jin, Shenglin Yang and Guang Li

      Article first published online: 24 JUN 2015 | DOI: 10.1002/adem.201500144

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      PLA/pearl composited scaffold has been successfully fabricated, which can obviously stimulate hydroxyapatite (HA) deposition compared with pristine PLA as measured by mineralization. MTT assay result demonstrates that pearl is beneficial to improve the biocompatibility of PLA. The cells show a more extended morphology on P20 than pristine PLA according to the SEM. As a result, the PLA/pearl composite material might be a superior candidate for bone repair.

    3. Phase Transformations in Ti–Fe Alloys Induced by High-Pressure Torsion

      B. B. Straumal, A. R. Kilmametov, Yu. Ivanisenko, A. S. Gornakova, A. A. Mazilkin, M .J. Kriegel, O. B. Fabrichnaya, B. Baretzky and H. Hahn

      Article first published online: 23 JUN 2015 | DOI: 10.1002/adem.201500143

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      Severe plastic deformation by high-pressure torsion (HPT) leads to the strong grain refinement in Ti-based alloys and to the formation of high-pressure ω-Ti-phase. However, the ω-Ti-phase disappears in the Ti–Fe alloys with increasing contain of iron, and only the α+β mixture remains (see the dark field TEM micrograph of the Ti–10 wt% Fe alloy after HPT).

  4. Review

    1. Formation of Corrosion-Resistant Thermal Diffusion Boride Coatings

      Eugene Medvedovski

      Article first published online: 19 JUN 2015 | DOI: 10.1002/adem.201500102

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      Corrosion resistance of iron boride-based coatings obtained through thermal diffusion process has been studied in the environments simulating some oil production conditions. These coatings demonstrated superior performance compared to untreated steels due to high structural and chemical stability of iron borides dealt with their thermodynamic properties and strong Fe-B and B-B covalent bonds, specific coating structure and good adhesion to steel substrates.

  5. Full Papers

    1. Enhanced Photocurrent Generation in Graphene/Copper Phthalocyanine/Mg–Al-Layered Double Hydroxide Layer-by-Layer Multilayers

      Qinzheng Yang, Jing Yang, Fujiao Jiang and Huazhang Zhao

      Article first published online: 19 JUN 2015 | DOI: 10.1002/adem.201500224

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      Visible-light-driven-photovoltaic G/TSCuPc/LDH nanofilms are prepared by LBL method based on electrostatic interaction. This preparation strategy endows a high content and a homogeneous dispersion of grapheme and TSCuPc in the polymer matrix, enhancing photocurrent generation in this novel system.

  6. Communications

    1. Bi-Functional Mechanism in Degradation of Toxic Water Pollutants by Catalytic Amorphous Metals

      Santanu Das, Seth Garrison and Sundeep Mukherjee

      Article first published online: 19 JUN 2015 | DOI: 10.1002/adem.201500239

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      AZO dye is a toxic water pollutant and carcinogen used widely as a coloring agent in textile industries. Efficient catalytic degradation of AZO dye by aluminum based metallic glass particles is presented in this report. The high catalytic activity originates from the simultaneous ionization of the transition metals in the alloy, which help in charge transfer to the [BOND]N[DOUBLE BOND]N[BOND] bonds in AZO dye, resulting in rapid degradation of AZO dye in an aqueous medium.

  7. Full Papers

    1. Mechanical Characterization of PM2000 Oxide-Dispersion-Strengthened Alloy by High Temperature Nanoindentation

      Ude Hangen, Chun-Liang Chen and Asta Richter

      Article first published online: 15 JUN 2015 | DOI: 10.1002/adem.201500095

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      High temperature nanoindentation in the Hysitron xSol up to 700 °C at small loads has been applied for the first time to measure mechanical properties of PM2000 ODS steel. The hardness drop at 400 °C is also reflected in the creep analysis that indicates a change in the strengthening mechanism.

    2. Oxidation Behavior of Al8Co17Cr17Cu8Fe17Ni33, Al23Co15Cr23Cu8Fe15Ni15, and Al17Co17Cr17Cu17Fe17Ni17 Compositionally Complex Alloys (High-Entropy Alloys) at Elevated Temperatures in Air

      Haneen M. Daoud, Anna M. Manzoni, Rainer Völkl, Nelia Wanderka and Uwe Glatzel

      Article first published online: 15 JUN 2015 | DOI: 10.1002/adem.201500179

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      High-temperature oxidation behavior for different kinds of high-entropy alloys has been highlighted. The oxidation behavior depends on the chemical composition of the alloy. The sufficient mole fraction of Al and Cr in the fcc-alloy enables the formation of both alumina- and chromia-protective scales. Only alumina scale formed in the bcc- and reference-alloys enhances the spallation at 1 000 °C.

    3. Core/Shell Iron/Oxide Nanoparticles for Improving the Magneto-Dielectric Properties of Polymer Composites

      Ta-I Yang, Chun-Yu Chuang, Shu-Chian Yang, Leo C. Kempel and Peter Kofinas

      Article first published online: 15 JUN 2015 | DOI: 10.1002/adem.201500234

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      A simple method to obtain high magnetic permeability (μr), high dielectric permittivity (ϵr), and low loss polymer composites with core/shell iron/metal oxide particles is developed. The layers of SiO2 or TiO2 on the magnetic Fe0 particle provide electrical insulting layers which decrease energy loss and also prevent the possibility of µr decrease due to Fe0 oxidation. Furthermore, using TiO2 to modify Fe0 surfaces improve ϵr of Fe@TiO2 without compromising its µr.

    4. Aging Processes in Ultrafine-Grained Low-Alloyed Bronzes Subjected to Equal Channel Angular Pressing

      Sergey V. Dobatkin, Natalia R. Bochvar and Daria V. Shangina

      Article first published online: 12 JUN 2015 | DOI: 10.1002/adem.201500099

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      The aging processes in ultrafine-grained (UFG) bronzes alloyed with Cr and Hf after equal channel angular pressing (ECAP) has been studied. It is shown that the ECAP leads to a considerable strengthening due to the UFG structure formation. The subsequent aging results in additional hardening and an increase in electrical conductivity at the expense of decomposition of supersaturated solid solution.

    5. Thermal Shock Study on Different Advanced Ceramics by Laser Irradiation in Different Media

      Robert Pulz, Birgit Rehmer, Gerold A. Schneider and Birgit Skrotzki

      Article first published online: 12 JUN 2015 | DOI: 10.1002/adem.201500162

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      The thermal shock behavior of three ceramics is characterized applying a heating-up laser thermal shock. The time- and space-resolved measurement of the temperature distribution allows the calculation of the local stress state as a function of time. The thermal shock strength is highest for SSiC and lowest in Al2O3 with MgO–PSZ in between. The investigated environment does not affect the thermal shock resistance under the studied experimental conditions.

    6. Influence of Ti3SiC2 Fiber Coating on Interface and Matrix Cracking in an SiC Fiber-Reinforced Polymer-Derived Ceramic

      Ina Filbert-Demut, Guoping Bei, Till Höschen, Johann Riesch, Nahum Travitzky and Peter Greil

      Article first published online: 12 JUN 2015 | DOI: 10.1002/adem.201500192

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      The effect of Ti3SiC2 coatings on the interfacial properties of SiC fiber-reinforced FeSiCr/SiC-filled polymethylsilsesquioxane derived ceramics as a variation of the coating thickness is investigated. Increased debonding and friction strength were observed in the modified composites compared to the uncoated interfaces.

    7. Formation of Cuboidal Co3AlC Precipitates in Carbon-Containing Co–Al–W-Based Superalloys

      Lisa Patricia Freund, Alexander Bauer, Lisa Benker, Steffen Neumeier and Mathias Göken

      Article first published online: 11 JUN 2015 | DOI: 10.1002/adem.201500171

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      C is added to a Co–Al–W alloy, which leads to the formation of small, ordered, cuboidal γ′ precipitates with high solvus temperature. In the Co–Al–W–C system, W is found to partition to the γ matrix while it distributes predominantly to the γ′ precipitates in the ternary Co–Al–W system. The cuboidal phase was therefore identified as E21-structured Co3AlC.

    8. Hybrid Filtration Membranes incorporating Nanoporous Silica within a Nanoscale Alumina Fibre Scaffold

      Veronica Mei Tiing Su and Trevor William Clyne

      Article first published online: 11 JUN 2015 | DOI: 10.1002/adem.201500220

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      Membranes comprising assemblies of (10–20 nm) alumina fibres, with or without nanoporous silica in the interstices, have outstanding filtration performance. The figure demonstrates that small (≈ 2 nm diameter) dye molecules can be filtered, and also that charge-related effects can operate.

    9. On the Thermodynamics and Kinetics of TCP Phase Precipitation in Re- and Ru- Containing Ni-base Superalloys

      Kamil Matuszewski, Alexander Müller, Nils Ritter, Ralf Rettig, Krzysztof J. Kurzydłowski and Robert F. Singer

      Article first published online: 11 JUN 2015 | DOI: 10.1002/adem.201500173

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      The tendency of Ni-base superalloys to precipitate TCP phases is significantly dependent on the variations in chemical composition. Two elements, Re and Ru, are especially important in respect to this problem. Re exhibits an inhomogeneous, while Ru homogenous distribution within the dendritic structure. Both elements influence the driving force for TCP phase precipitation.

    10. Influence of Thermal Fiber Pretreatment on Microstructure and Mechanical Properties of C/C-SiC with Thermoplastic Polymer-Derived Matrices

      Florian Reichert, Nico Langhof and Walter Krenkel

      Article first published online: 8 JUN 2015 | DOI: 10.1002/adem.201500193

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      Two thermoplastic polymers, polyetheretherketone and polyetherimide, are examined in terms of their suitability as carbon precursors for C/C-SiC composites. The carbon fibers are thermally pretreated in nitrogen atmosphere and show decreasing oxygen concentrations on the surface at higher pretreatment temperatures. This is the main effect for a reduction of the fiber-matrix bonding, resulting in increasing SiC amounts and fiber-pull-out effects of the ceramic matrix composites.

    11. Corrosion Behaviour of Al–4Mg–1Cu (wt%) Microalloyed with Si and Ag

      R. K. Gupta, C. Li, J. Xia, X. Zhou, G. Sha, B. Gun, S. P. Ringer and N. Birbilis

      Article first published online: 8 JUN 2015 | DOI: 10.1002/adem.201500163

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      The mechanical and corrosion properties of Al-alloys, which depend upon microstructure, can be optimized via the combination of suitable thermomechanical processing and alloy composition. The addition of 0.4 wt% Ag to Al–4Mg–1Cu–0.5Si simultaneously increases the age hardening response and corrosion resistance in the peak aged condition.

  8. Communications

    1. Interfacial Energy Effect on the Distribution of Ag3Sn in Full Intermetallic Joints

      Ting-Li Yang, Zi-Xuan Zhu, Jen-Jui Yu, Yan-Fu Lin and C. Robert Kao

      Article first published online: 5 JUN 2015 | DOI: 10.1002/adem.201500153

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      At the triple junction between two Cu6Sn5 grains and an Ag3Sn grain (red-dotted circle), there is a clear grooving into the grain boundary of the two neighboring Cu6Sn5 grains. The low interfacial free energy between Ag3Sn and Cu6Sn5 is responsible for the observation. The ratio of the interfacial energy is shown to be Cu6Sn5-Cu6Sn5:γAg3Sn-Ag3Sn:γAg3Sn-Cu6Sn5 = 1.8:1.08:1. Compared to well-known grain boundary penetration of metal grains by a second molten metals, it is observed for the first time that an intermetallic compound is able to penetrate the grain boundary of a second intermetallic compound because of low interfacial free energy between Ag3Sn and Cu5Sn5.

  9. Reviews

    1. Mechanical Properties of Ultrafine-Grained Metals: New Challenges and Perspectives

      Alexei Vinogradov

      Article first published online: 5 JUN 2015 | DOI: 10.1002/adem.201500177

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      An enhancement of strength concurs with a great loss of ductility in UFG metals produced by severe plastic deformation. Experimental data are reviewed, and a phenomenological dislocation kinetics-based model approach is proposed to provide a unified view for the hardening behavior and early macroscopic strain localization in UFG materials.

  10. Full Papers

    1. Mechanical and Microstructural Investigation of Nickel-Based Superalloy IN718 Manufactured by Selective Laser Melting (SLM)

      Johannes Strößner, Michael Terock and Uwe Glatzel

      Article first published online: 5 JUN 2015 | DOI: 10.1002/adem.201500158

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      IN718 manufactured by selective laser melting (SLM) is investigated regarding its mechanical and microstructural properties. Optical, scanning, and transmission electron microscopy are carried out in order to characterize the microstructure explicitly. Mechanical tests include tensile testing at room temperature and at elevated temperatures and hardness measurements. The material is investigated in the “as built” state and after two different heat treatments.

    2. Synthesis of Hybrid Materials by Severe Plastic Deformation: A New Paradigm of SPD Processing

      Yan Beygelzimer, Yuri Estrin and Roman Kulagin

      Article first published online: 2 JUN 2015 | DOI: 10.1002/adem.201500083

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      The claim in this article is that established techniques of severe plastic deformation are ideally suited for producing advanced hybrid materials. Their advantage is the possibility to combine nanostructuring with the formation of specially designed inner architecture of the hybrids. This establishes a new paradigm in research on hybrid materials.

    3. Mechanical Properties and Tensile Fracture Mechanisms of Fe–Mn–(Al, Si) TRIP/TWIP Steels with Different Ferrite Volume Fractions

      Fu Yuan Dong, Jian Chao Pang, Peng Zhang, Qi Qiang Duan and Zhe Feng Zhang

      Article first published online: 1 JUN 2015 | DOI: 10.1002/adem.201500108

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      The article focuses on mechanical properties and fracture behaviors of four Fe–Mn–(Al, Si) TRIP/TWIP steels with different ferrite volume fractions. There are three fracture modes for the steels due to the variation of the fracture stress and the macroscopic instability stress: fully normal fracture for Fe–15Mn–Al–Si steel (hard ferrite matrix and austenite second phase); necking + normal fracture for Fe–20Mn–Al–Si steel (ductile austenite matrix and ferrite second phase); and necking + shear fracture for Fe–(25, 30)Mn–Al–Si steel (fully austenite phase).

    4. On the Processing Pathway Dependence of Microstructure Evolution During Severe Plastic Deformation: Nickel as a Case Example

      Daria Prokoshkina, Anna Moros, Gerrit Reglitz, Guru Prasad Dinda, Dmitrij D. Kuznetsov, Vladimir V. Popov, Alexey V. Stolbovsky, Evgeniy Shorohov, Sergiy V. Divinski and Gerhard Wilde

      Article first published online: 1 JUN 2015 | DOI: 10.1002/adem.201500174

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      Comparison of the results such as the microhardness as function of grain size obtained on Nickel processed along different processing pathways indicates that the extreme states achieved by SPD seem in fact to be achievable also by more conventional processes such as rolling-based deformation routes that offer access to industrial processing schemes.

    5. Serrated Flow Behavior of Titanium-Based Composites with Different In Situ TiC Contents

      Chao Yang, Zhi Ding, Jianan Lin, Shengguan Qu, Xiaoqiang Li, Weiwen Zhang and Yuanyuan Li

      Article first published online: 1 JUN 2015 | DOI: 10.1002/adem.201500145

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      The fabricated titanium matrix composites (TMCs) with 2.5 (TMC 2.5) and 7.5 vol% (TMC 7.5) in situ TiC contents have invariable plasticity and ultimate compression stress. This can be explained by establishing a relationship between serrated flow behavior of stress–strain curves and shear-band interactions during plastic deformation in the TMCs.

    6. Deformation Behavior and Microstructural Evolution of Cu–Ag Alloys Processed by High-Pressure Torsion

      Karoline S. Kormout, Bo Yang and Reinhard Pippan

      Article first published online: 29 MAY 2015 | DOI: 10.1002/adem.201500109

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      In order to investigate the deformation behavior of composites in immiscible systems, different Cu–Ag alloys are produced by high-pressure torsion processing. Their microstructural evolution from lamellar ultrafine-grained to nanocrystalline is analyzed and related to mechanical properties.

    7. Elastomeric Actuators on Airfoils for Aerodynamic Control of Lift and Drag

      Jingjin Xie, James B. McGovern, Rutvij Patel, Woobiehn Kim, Saugata Dutt and Aaron D. Mazzeo

      Article first published online: 26 MAY 2015 | DOI: 10.1002/adem.201500036

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      Xie et al. at Rutgers University design, fabricate, and characterize unique airfoils embedded with inflatable, elastomeric actuators. By controlling the actuators, these new airfoils can obtain significant increases in lift (20–300%) at low angles of attack, while increasing stall angles. This work marks a step forward in a new area of research focused on dynamic fluid–soft material interactions.

    8. Quantitative Analyses of MWCNT-Ti Powder Mixtures using Raman Spectroscopy: The Influence of Milling Parameters on Nanostructural Evolution

      Khurram S. Munir, M. Qian, Yuncang Li, Daniel T. Oldfield, Peter Kingshott, De Ming Zhu and Cuie Wen

      Article first published online: 20 MAY 2015 | DOI: 10.1002/adem.201500142

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      Harsh ball milling conditions create structural disorders such as non-sp2 defects in the form of open edges and vacancies in the C–C system of MWCNTs. These open edges (existing along the side walls) and vacancies provide the potential sites for the formation of interfacial reaction products of titanium carbides (TiC).

    9. Ultrafine Grained Structures Resulting from SPD-Induced Phase Transformation in Al–Zn Alloys

      Xavier Sauvage, Maxim Yu. Murashkin, Boris B. Straumal, Elena V. Bobruk and Ruslan Z. Valiev

      Article first published online: 19 MAY 2015 | DOI: 10.1002/adem.201500151

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      We have investigated microstructures resulting from the concomitant mechanisms of grain refinement and phase separation in Al–Zn alloys processed by SPD. We show that a higher processing temperature could give rise to a finer structure because of a competition between the classical discontinuous precipitation of Zn and SPD-induced dynamic precipitation.

    10. Reasons for Volume Contraction after Long-Term Annealing of Waspaloy

      Svenja Kinzel, Johannes Gabel, Rainer Völkl and Uwe Glatzel

      Article first published online: 19 MAY 2015 | DOI: 10.1002/adem.201500159

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      The influence of long-term annealing on sample length and microstructure of Ni-base alloy Waspaloy is investigated. Sample contraction during annealing is caused by microstructural changes. Changes in the volume fraction of γ′ phase and matrix are accompanied by compositional differences which influence the lattice parameter. Another contribution to length change is given by carbide transformation.

    11. Anisotropic Spreading Behavior of PAO Oil on Laser-Patterned Stainless Steel Surfaces

      Andreas Rosenkranz, Simon Fleischmann, Carsten Gachot and Frank Mücklich

      Article first published online: 18 MAY 2015 | DOI: 10.1002/adem.201500115

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      We study the spreading behavior of line-like surface patterns produced by laser interference patterning. This study demonstrates that smaller periodicities and larger aspect ratios lead to an enhanced anisotropic spreading behavior due to a larger number of pinning centers.

    12. Additive Manufacturing and Characterization of René 80 Superalloy Processed Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair

      Ranadip Acharya, Rohan Bansal, Justin J. Gambone, Max A. Kaplan, Gerhard E. Fuchs, Suman Das and N. G. Rudawski

      Article first published online: 15 MAY 2015 | DOI: 10.1002/adem.201400589

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      Scanning laser epitaxy produces thick, crack-free deposits of René 80, a high γ′ “non-weldable” superalloy, atop investment cast substrates of the same alloy in a single pass. Microstructural refinement and increased hardness are observed in the deposit compared to the as-cast substrate.

    13. Influence of the Carbon Content on the Crystallization and Oxidation Behavior of Polymer-Derived Silicon Carbide (SiC)

      Tobias Lehmann, Johannes Baier, Andreas Leineweber, Andreas Kienzle and Joachim Bill

      Article first published online: 15 MAY 2015 | DOI: 10.1002/adem.201500064

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      Based on experimental data, we propose a model describing the influence of the carbon content on the crystallization and oxidation behavior of precursor-derived SiC. Until forming a passivating SiO2 layer, the mass loss during oxidation is formed dependent on the carbon content of the SiC.

    14. High Temperature Mechanical Properties of an Extruded Mg–TiO2 Nano-Composite

      Athar Safari and Reza Mahmudi

      Article first published online: 15 MAY 2015 | DOI: 10.1002/adem.201500132

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      Mechanical properties of pure Mg and Mg-1%TiO2 nano-composite are evaluated in the temperature range 25–225 °C. Depending on the test temperature, the ultimate shear strength increases by 4–12 MPa, and the hardness by 4–8 Hv in the composite material. The achieved strengthening is caused by dispersive distribution of the nano-sized TiO2 particles in the Mg matrix.

  11. Communications

    1. Modeling of Metal Flow during Processing by Multi-ECAP-Conform

      Elvira I. Fakhretdinova, Georgy I. Raab and Ruslan Z. Valiev

      Article first published online: 13 MAY 2015 | DOI: 10.1002/adem.201500125

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      The article is focused on the studies of the new SPD processing technique of Multi-ECAP-Conform. To evaluate the influence of the tool geometry, four design versions are considered. The schemes are compared on the basis of the following parameters: strain rate, strain degree, stress intensity, and contact stresses. To estimate the parameters, virtual modeling by the finite-element method with the Deform-3D software is employed.

  12. Communication

    1. A Novel Strong and Ductile TWIP/Martensite Steel Composite

      O. Bouaziz, J. P. Masse, G. Petitgand and M. X. Huang

      Article first published online: 8 MAY 2015 | DOI: 10.1002/adem.201500113

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      A bi-layered steel composite consisting of a martensitic steel and a twinning-induced plasticity (TWIP) steel is fabricated by roll bonding. The steel composite possesses the advantages of TWIP (high ductility) and martensitic steels (high yield stress) so that it has simultaneously high yield stress and high uniform elongation.

  13. Communications

    1. Functionally Graded Ti-6Al-4V Meshes with High Strength and Energy Absorption

      Shujun Li, Shuo Zhao, Wentao Hou, Chunyu Teng, Yulin Hao, Yi Li, Rui Yang and R. D. K. Misra

      Article first published online: 5 MAY 2015 | DOI: 10.1002/adem.201500086

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      Graded/gradient Ti-6Al-4V mesh structures are fabricated by electron beam melting. The results of compressive properties indicate that the deformation behavior of these graded meshes is the weighted average of stress–strain response of each uniform mesh constituents. Through appropriate design of property and volume fraction of each constituents, graded/gradient meshes with high strength and energy absorption can be fabricated.

  14. Full Papers

    1. The Influence of Grain Size Determination Method on Grain Growth Kinetics Analysis

      Leyla Hashemi-Sadraei, S. Ebrahim Mousavi, Enrique J. Lavernia and Julie M. Schoenung

      Article first published online: 3 MAY 2015 | DOI: 10.1002/adem.201500057

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      A thermally stable nanocomposite is annealed to investigate the effect of different XRD-based grain size determination methods on grain growth kinetics analysis. The application of these different methods leads to differences in calculated rate constants and activation energies and mechanistic explanations. Reproducibility is also evaluated.

    2. Some Physical Characteristics of Strain Hardening in Severe Plastic Deformation

      Yan Beygelzimer, Laszlo S. Toth and John J. Jonas

      Article first published online: 3 MAY 2015 | DOI: 10.1002/adem.201500097

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      Using group theory it is shown that the von Mises strain is valid for both simple shear and tension/compression, while the Hencky strain is valid only for the latter. In large strain hardening, microstructure self-similarity results in power law hardening and deviations between curves of different strain paths are due to differences in slip system activity and textures.

    3. Effect of Severe Cold or Warm Deformation on Microstructure Evolution and Tensile Behavior of a 316L Stainless Steel

      Marina Odnobokova, Andrey Belyakov and Rustam Kaibyshev

      Article first published online: 30 APR 2015 | DOI: 10.1002/adem.201500100

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      The nanocrystalline 316L stainless steel is processed by large strain cold or warm rolling. The development of nanocrystalline structures is accompanied by significant strengthening. The yield strength increases from 235 MPa in the original annealed state to 1 680 or 1 070 MPa after rolling to a strain of 3 at 293 or 573 K, respectively.

    4. The Microstructure Evolution of a High Zr-Containing WE Magnesium Alloy Through Isothermal Semi-Solid Treatment

      M. Moradjoy-Hamedani, A. Zarei-Hanzaki, S. M. Fatemi and Sh. Asqardoust

      Article first published online: 30 APR 2015 | DOI: 10.1002/adem.201500087

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      In this communication, isothermal semi-solid heat treatment is introduced as a viable manufacturing route to produce non-dendritic semi-solid slurry of a high Zr-containing Mg-Y-RE-Zr alloy and to redistribute contained Zr-rich particles. This limits the growth of the solid particles. Increasing the isothermal temperature and holding time lead to an increase in liquid fraction, shape factor, and particle size.

    5. Mechanical Behavior of an Al–Mg–Mn–Sc Alloy with an Ultrafine Grain Structure at Cryogenic Temperatures

      Daria Zhemchuzhnikova and Rustam Kaibyshev

      Article first published online: 30 APR 2015 | DOI: 10.1002/adem.201500138

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      In this paper, the effect of a grain size of an Al–Mg–Mn–Sc alloy on the mechanical and fracture behavior at temperatures ranging from 77 to 293 K was examined. It is shown that the ductility of the alloy with the fine grain structure increases with decreasing temperature due to an increase in the strain-hardening rate.

    6. A New Process for the Thermal Treatment of Calcium Phosphate Coatings Electrodeposited on Ti6Al4V Substrate

      Nader Ben Jaber, Richard Drevet, Joël Fauré, Clémence Demangel, Sylvain Potiron, Ahmed Tara, Ahmed Ben Cheikh Larbi and Hicham Benhayoune

      Article first published online: 29 APR 2015 | DOI: 10.1002/adem.201400572

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      A new experimental process for the thermal treatment of prosthetic coatings is developed. This thermal treatment, named THUCA, uses a controlled atmosphere obtained by Argon injection under vacuum. It allows to obtain a fully crystallized biphasic coating with improved cohesion and adhesion to the titanium alloy substrate.

    7. Effect of Fabricating Parameters on Morphology and Photocatalytic Performance of CdS NCs/TiO2 NTs Photoelectrode for Decomposition of Organic Pollutants

      Xiuwen Cheng, Guoping Pan and Xiujuan Yu

      Article first published online: 27 APR 2015 | DOI: 10.1002/adem.201500049

      Thumbnail image of graphical abstract

      In this study, CdS NCs/TiO2 NTs photoelectrode is fabricated through anodization, followed by electrodeposition strategy. Meanwhile, some critical parameters are optimized through morphologies observation and PC decomposition of rhodamine B (RhB). Results show that the influence of fabricating parameters for degradation of RhB aqueous solution fitted well with the pseudo-first-order kinetics function.

    8. Solid-State Foaming by Oxide Reduction and Expansion: Tailoring the Foamed Metal Microstructure in the Cu–CuO System with Oxide Content and Annealing Conditions

      Mark A. Atwater, Kris A. Darling and Mark A. Tschopp

      Article first published online: 27 APR 2015 | DOI: 10.1002/adem.201500063

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      Copper foam is created by the reduction of a ball-milled Cu–CuO composite. Final density is dependent on time and temperature, but very small pore and grain sizes are achieved under all processing conditions. This presents unique implications for creating tailored foam structures in loose powder as well as in bulk parts created via powder metallurgy.

    9. Dynamic Behavior of Vertically Aligned Carbon Nanotube Foams With Patterned Microstructure

      Ludovica Lattanzi, Ramathasan Thevamaran, Luigi De Nardo and Chiara Daraio

      Article first published online: 22 APR 2015 | DOI: 10.1002/adem.201400571

      Thumbnail image of graphical abstract

      Micropatterned VACNT foams are fabricated to investigate the relationship between the structure and the bulk dynamic response. Changes in the patterns' geometry allow tuning the specific energy absorption of VACNTs under impact loading, and result in materials with significantly reduced bulk density. The study confirms that patterned VACNT foams hold great potential as novel lightweight material for impact protection.

    10. Cushioning and Energy Absorbing Property of Combined Aluminum Honeycomb

      Yu-Liang Lin, Zhi-Feng Zhang, Rong Chen, Yan Li, Xue-Jun Wen and Fang-Yun Lu

      Article first published online: 22 APR 2015 | DOI: 10.1002/adem.201400574

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      Out-of-plane crushing behavior of combined aluminum honeycomb sample is investigated. Inserting processes between different honeycombs smooth the stress curve and lower the stress level, which is beneficial to the optimization design of aluminum honeycomb buffer.

    11. Production of Clad Steel Strips by Twin-Roll Strip Casting

      Michele Vidoni, Rebecca Ackermann, Silvia Richter and Gerhard Hirt

      Article first published online: 22 APR 2015 | DOI: 10.1002/adem.201500094

      Thumbnail image of graphical abstract

      Cladding by twin-roll strip casting of a combination of the austenitic stainless steel 1.4301 and the carbon steel 1.1248 was investigated. This production method is based on the introduction of a solid strip between the casting rolls, where the joining takes place. For the first time this process is used to combine two steel alloys. Shear tests with an optimized shearing surface are used to measure the mechanical resistance of the clad joint.

  15. Communications

    1. Synthesis and Characterization of TiAl-Based Nanocomposites by a Melt Electromagnetic Stirring Process

      Zhiyong Zhang, Yanli Wang, Xiangjun Xu, Yongfeng Liang, Laiqi Zhang and Junpin Lin

      Article first published online: 21 APR 2015 | DOI: 10.1002/adem.201400557

      Thumbnail image of graphical abstract

      γ-TiAl-based nanocomposites have been synthesized by an electromagnetic stirring process; finely dispersed nanoparticles are obtained with the aid of reactive wetting; the wettability of the studied nanoparticles are sorted in descending order as TiO2 > TiC > Al2O3 > Y2O3, and TiAl/TiC nanocomposite has a high microhardness of 450 HV. Effects of the nanoparticles on solidification process and the cast microstructures are discussed.

  16. Full Papers

    1. High Strength and Electrical Conductivity of Al-Fe Alloys Produced by Synergistic Combination of High-Pressure Torsion and Aging

      Jorge M. Cubero-Sesin, Makoto Arita and Zenji Horita

      Article first published online: 21 APR 2015 | DOI: 10.1002/adem.201500103

      Thumbnail image of graphical abstract

      High pressure torsion (HPT) processing and aging was applied to Al-Fe alloys with different initial states. An adimensional figure of merit is proposed to ponder both the strength and electrical conductivity. The figure of merit is plotted with respect to the strain imposed by HPT, showing the superior properties of Al-2%Fe, particularly after peak-aging (0.5 h) which shows recovery of electrical conductivity from precipitation of nano-sized Fe-rich particles.

    2. Flow Curve Evolution During Cyclic Processing of Ultrafine-Grained Aluminum Alloy by Multiaxial Forging

      Peter Bereczki and Gyorgy Krallics

      Article first published online: 20 APR 2015 | DOI: 10.1002/adem.201400588

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      This study aims to present a procedure to describe the evolution of flow stress during multiaxial forging, based on the direct calculation of the flow curves from the measured data. The effect of the applied strain amplitude on the calculated flow curves and on the resultant microstructure is also investigated, as shown in the following figure.

    3. Finite Element Analysis of Crack Propagation in AlSi7%Mg0.3% Cast Alloys using Macro- and Micro-Scale Levels

      Galina Lasko, Ulrich Weber, Markus Apel, Ralf Berger and Siegfried Schmauder

      Article first published online: 17 APR 2015 | DOI: 10.1002/adem.201500051

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      Within the framework of the finite element method (FEM) CT-test experiments are simulated on the macroscale and on the microscale levels with application of cohesive zone model. Two-scale simulations are performed placing the cut-out of the microstructure with two kinds of porosities (larger pores and smaller pores) but with the same volume fraction of porosity into the macro C(T) specimen. The effect of different pore sizes at the same volume fraction of pores on fracture toughness is observed.

    4. Polymer-Derived Ceramic Coil Springs

      Sofia Loginkin, Lorenz Schlier, Joseph Harris, Nahum Travitzky and Peter Greil

      Article first published online: 15 APR 2015 | DOI: 10.1002/adem.201500025

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      Novel polymer-derived ceramic coil springs were manufactured via thermoplastic coiling of extruded filaments with subsequent two-step heat treatment under flowing nitrogen atmosphere at ambient pressure. Formation of a multiphase reaction composite microstructure combined with a dense surface reaction zone give rise to enhanced mechanical properties of the polymer-derived ceramic coil springs without surface machining. Thus, the springs may benefit from surface defect healing capacity. Thermoplastic deformation behavior of filler-loaded polymer composite feedstocks makes polymer-shaping techniques attractive for ceramic spring manufacturing.

    5. Mesoporous Siloxane Films Through Thermal Oxidation of Siloxane–Carbon Nanocomposites

      Kamil Zuber, Drew R. Evans, Stuart McClure and Peter J. Murphy

      Article first published online: 13 APR 2015 | DOI: 10.1002/adem.201500066

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      These nanocomposite thin films are prepared via atmospheric plasma enhanced chemical vapour deposition, using a variety of carbonaceous precursors. While the nanocomposite appears dark in colour, after oxidation the mesoporous thin film is quite transparent. SEM analysis of secondary and backscattered electrons is used as a semi-quantitative method to study the transition from the nanocomposite to mesoporous material.

    6. Increased Shape Stability and Porosity of Highly Porous Injection-Molded Titanium Parts

      Alexander M. Laptev, Natália F. Daudt, Olivier Guillon and Martin Bram

      Article first published online: 8 APR 2015 | DOI: 10.1002/adem.201500061

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      Highly porous titanium parts were produced by metal injection molding and the space holder technique. The dissolution of the KCl space holder in water was replaced with sublimation during vacuum sintering. This improvement enabled titanium parts to be manufactured without sample collapse or shape distortion. Final porosities were close to the recommended value for spinal implants. The time-consuming leaching step was also omitted.

  17. Communications

    1. An Innovative Way to Produce γ-TiAl Blades: Spark Plasma Sintering

      Thomas Voisin, Jean-Philippe Monchoux, Lise Durand, Nikhil Karnatak, Marc Thomas and Alain Couret

      Article first published online: 7 APR 2015 | DOI: 10.1002/adem.201500019

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      In this Communication, it is shown that the production of turbine blades in γ-TiAl alloys through Spark Plasma Sintering (SPS) is a viable manufacturing route, by demonstrating that near-net shaping of γ-TiAl blades is successful, and by developing an alloy with balanced and outstanding mechanical properties at room and high temperatures in a single run and without subsequent thermal treatments.

  18. Full Papers

    1. Influence of the Scanning Strategy on the Microstructure and Mechanical Properties in Selective Electron Beam Melting of Ti–6Al–4V

      Thorsten Scharowsky, Vera Juechter, Robert F. Singer and Carolin Körner

      Article first published online: 7 APR 2015 | DOI: 10.1002/adem.201400542

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      In the present work, a parameter field for the scan speed and beam power was observed regarding the influence of the scanning parameters on the microstructure. It can be shown, that the α platelet thickness can directly be influenced. The results correspond very well to the Hall–Petch relation.

    2. Effect of Annealing Atmosphere on the Recrystallized Texture and Abnormal Grain Growth of Ni–5%W Alloy Sheets

      Yanick Ateba Betanda, Anne-Laure Helbert, François Brisset, Thierry Waeckerlé and Thierry Baudin

      Article first published online: 7 APR 2015 | DOI: 10.1002/adem.201500071

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      This paper details and compares the effect of two annealing atmospheres (hydrogen and argon) on recrystallized texture and abnormal grain growth (AGG) of Ni5%W alloys sheets. It is shown that hydrogen promotes the cube texture development, while argon slows down its development. Besides, it is shown that hydrogen favors the triggering of AGG at a temperature higher than 1 120 °C, while under argon, abnormal grain growth is not observed before 1 200 °C. Then, an optimized annealing process has been put forward combining both atmospheres in order to increase the fraction of cube orientation without triggering AGG.

    3. High-Temperature Micropillar Compression Creep Testing of Constituent Phases in Lead-Free Solder

      Carl R. Mayer, Saeid Lotfian, Jon Molina-Aldareguia and Nikhilesh Chawla

      Article first published online: 7 APR 2015 | DOI: 10.1002/adem.201500089

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      As the size of solder interconnects used in electronics packaging decreases, methods for characterizing the creep behavior of solder at ever smaller length scales need to be developed. Long duration micropillar compression experiments at constant loads and temperatures ranging from 60 to 160 °C are used to characterize the creep behavior in pure Sn (tin) dendrites and the Sn–Ag3Sn eutectic constituent in a lead-free Sn–3.5 Ag solder alloy.

    4. The Requirements for Superplasticity with an Emphasis on Magnesium Alloys

      Megumi Kawasaki, Roberto B. Figueiredo and Terence G. Langdon

      Article first published online: 7 APR 2015 | DOI: 10.1002/adem.201500068

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      Superplasticity refers to the unusually high elongations that may be achieved in some materials when pulling in tension. An example is shown in the Figure for a Zn–22% Al eutectoid alloy which was processed by high-pressure torsion and then pulled to failure at 473 K using an initial strain rate of 1.0 × 10−1 s−1.

    5. Solution Heat Treatment of the Single Crystal Nickel-Base Superalloy CMSX-4 Fabricated by Selective Electron Beam Melting

      Markus Ramsperger, Laís Mújica Roncery, Inmaculada Lopez-Galilea, Robert F. Singer, Werner Theisen and Carolin Körner

      Article first published online: 3 APR 2015 | DOI: 10.1002/adem.201500037

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      Selective electron beam melting (SEBM) manufacturing of CMSX-4 leads to a very fine solidification structure which is two orders of magnitude smaller than in conventional castings (e.g., Bridgman). Microprobe mappings of Re distribution in CMSX-4 can be used to show the differences in homogeneity (a and b). Due to the homogeneity, a solution heat treatment (HT) of 4 min (1320 °C) is already sufficient for homogenization of SEBM CMSX- 4 (c).

    6. Deformation Field Analysis in Equal Channel Angular Extrusion of Metals Using Asymmetric Flow Function

      Arman Hasani and Laszlo S. Toth

      Article first published online: 3 APR 2015 | DOI: 10.1002/adem.201500070

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      A general flow function which can be applied for any ECAE die angle is used to characterize the plastic deformation in this process. The function contains just three parameters; the parameter n that describes the sharpness of the flow line, and the m and αparameters that perform its asymmetry. The approach is applied to define the plastic deformation zone as well as the strain and strain rate field in 90° and 120° ECAE of pure aluminum. Suitability of the flow function is examined by simulation of crystallographic textures of pure copper obtained from the 135° ECAE die experiments.

    7. A Pseudo-Model Strategy Combining Experiment and Model to Investigate the Targeting Efficiency of Injected Magnetic Nanoparticles as Therapeutics Carriers

      Yanping Liu, Yanan Xue, Bo Yu, Sihui Long, Xiaogang Luo, Ning Cai and Faquan Yu

      Article first published online: 2 APR 2015 | DOI: 10.1002/adem.201500042

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      A strategy based on both the experiment and model was developed to predict targeting efficiency (TE) in magnetic drug targeting. Two processes of blood circulation clearance and targeting magnetic migration were first abstracted to depict the fate of injected magnetic particle. The model contains only two variables, or the half lives which represent the respective characteristic time for the two processes. Two magnetic particles were prepared with different mobility to evaluate the model in vitro. Experiments verified the reliability of the model. The model provides broad prediction of TE under the free choice of these variables.

    8. Effect of Strain Rate on Tensile Ductility and Fracture Behavior of Bulk Nanotwinned Copper

      Zesheng You and Lei Lu

      Article first published online: 1 APR 2015 | DOI: 10.1002/adem.201500073

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      A bulk preferentially nanotwinned copper is tensioned at different rates, which reveals a significant strain rate effect. The ductility, especially the post-necking elongation, reduces dramatically at low rates, associated with a transition from ductile dimple to evident intergranular fracture.

    9. Microstructures and Properties of Aluminum–Copper Lap-Welded Joints by Cold Metal Transfer Technology

      Jicai Feng, Yibo Liu, Qingjie Sun, Jinping Liu and Laijun Wu

      Article first published online: 30 MAR 2015 | DOI: 10.1002/adem.201400573

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      1 mm thick 1060 aluminum sheet and pure copper are joined using AlCu5 filler wire by cold metal transfer (CMT). The investigation focuses on the effect of heat input on the microstructure and tensile shear strength of joints. The bonding mechanism of Al/Cu-brazed joint and the fracture morphology is also analyzed.

    10. Specific Features of the Phase Composition and Structure of a High-Strength Multi-Component Fe–W–Mo–Cr–V–Si–Mn–C Steel Synthesized via Laser Remelting

      Vladimir G. Pushin, Natalia N. Kuranova, Nina V. Nikolaeva, Aleksei N. Uksusnikov, Yurii M. Ustyugov, Elena S. Belosludtseva, Artem V. Pushin and Aleksei E. Svirid

      Article first published online: 30 MAR 2015 | DOI: 10.1002/adem.201400581

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      The structure–phase composition of thin-sheet samples of Fe–W–Mo–Cr–V–Si–Mn–C steel synthesized via laser remelting is studied by methods of XRD, EDS, TEM, SEM, and LM. It is an ultrafine-grained ferrite–martensite matrix with M6C, M23C6, MC carbides, which provides 62-HRC hardness. Numerous features typical of high-entropy alloys are revealed.

    11. Heat Manipulation Using Highly Anisotropic Pitch-Based Carbon Fiber Composites

      Nikolaos Athanasopoulos and Nicolaos J Siakavellas

      Article first published online: 30 MAR 2015 | DOI: 10.1002/adem.201500085

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      High performance heat flux manipulation materials are proposed and analyzed using highly thermally and electrically anisotropic engineering materials in the microscale. Heat flux manipulation is achievable using continuous and highly anisotropic pitch-based carbon fiber composites. These homogeneous, highly anisotropic, and non-singular materials protect transiently critical regions and nullify the temperature gradient through the protected region.

  19. Communications

    1. Self-Assembled Ultra High Strength, Ultra Stiff Mechanical Metamaterials Based on Inverse Opals

      Jefferson J. do Rosário, Erica T. Lilleodden, Martin Waleczek, Roman Kubrin, Alexander Yu. Petrov, Pavel N. Dyachenko, Julian E.C. Sabisch, Kornelius Nielsch, Norbert Huber, Manfred Eich and Gerold A. Schneider

      Article first published online: 30 MAR 2015 | DOI: 10.1002/adem.201500118

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      Inverse opals are presented as a class of mechanical metamaterials. Pure silica and titania coated silica inverse opals show high strength- and modulus-to-weight ratios, even outperforming many optimized strut-based microfabricated ceramic materials. Micropillars were fabricated out of self-assembled layers and tested under compression. Their high performance is due to its arch-like structure, where stresses are smoothly directed into the regions of higher material mass, thereby mitigating the stress concentration at the pore perimeter, as confirmed by numerical simulations.

  20. Full Papers

    1. Enhanced Heterogeneous Nucleation by Pulsed Magneto-Oscillation Treatment of Liquid Aluminum Containing Al3Ti1B Additions

      Dong Liang, Jie Sun, Tianyu Liu, Qijie Zhai, Gui Wang, David H. StJohn, Hongbiao Dong and Honggang Zhong

      Article first published online: 27 MAR 2015 | DOI: 10.1002/adem.201400488

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      Pulsed Magneto-Oscillation (PMO) can significantly reduce the grain size of commercially pure Al containing a range of Al3Ti1B mater alloy. The grain size dose not follow a linear relationship with 1/Q after PMO. The grain density is largely increased by PMO and directly proportional to Ti content.

    2. Multifunctional Engineering Aluminum Surfaces for Self-Propelled Anti-Condensation

      Xu Jin, Xiyao Zhang, Yun Peng, Moyuan Cao, He Liu, Xiaohan Pei, Kesong Liu and Lei Jiang

      Article first published online: 27 MAR 2015 | DOI: 10.1002/adem.201500046

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      Self-propelled motion is ubiquitous in nature. The spontaneous anti-condensation on low adhesive superamphiphobic engineered Al surface was reported arising from surface energy released upon drop coalescence. The resultant Al surface also demonstrated superior repellency toward various polar, nonpolar liquids, and even corrosive liquids, possessing anti-corrosion, and self-cleaning properties.

    3. TEM Study of Schottky Junctions in Reconfigurable Silicon Nanowire Devices

      Sayanti Banerjee, Markus Löffler, Uwe Muehle, Katarzyna Berent, Walter Weber and Ehrenfried Zschech

      Article first published online: 25 MAR 2015 | DOI: 10.1002/adem.201400577

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      In the paper, the nickel silicide phase forming the Schottky junction in a silicon nanowire device is identified and characterized using high resolution TEM and EDX line scan. The sample was prepared using a lift-out process in FIB and corresponding low accelerating voltage ion milling. The EDX line scan data is provides a comprehensive idea about the structure of the Schottky junction, which is essential for the engineering and theoretical modeling of the said junction.

    4. Carbon Fiber/Carbon Nanotube Buckypaper Interply Hybrid Composites: Manufacturing Process and Tensile Properties

      Shaokai Wang, Rebekah Downes, Charles Young, David Haldane, Ayou Hao, Richard Liang, Ben Wang, Chuck Zhang and Rob Maskell

      Article first published online: 19 MAR 2015 | DOI: 10.1002/adem.201500034

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      Carbon nanotube sheet was successfully integrated into carbon fiber composites to create hybrid multifunctional structural composite materials. In this study, nano/micro dual-scale resin flow characteristics and quality control in the autoclave process of manufacturing hybrid composite laminates were investigated. This hybrid composites had competitive strength and modulus, and resulted in dramatic improvements in both in-plane and through-thickness electrical conductivities.

    5. Gradient Structure in High Pressure Torsion Compacted Iron Powder

      Yajun Zhao, Roxane Massion, Thierry Grosdidier and Laszlo S. Toth

      Article first published online: 19 MAR 2015 | DOI: 10.1002/adem.201500012

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      High Pressure Torsion (HPT) technique is a promising and efficient process for consolidating metal powders by imposing severe shear deformation and high hydrostatic pressure to the samples. Iron powder is compacted successfully into solid disk by HPT at room temperature. The homogeneity of shear strain across the thickness of the disk displays a gradient distribution. The strain gradient leads to the formation of three regions throughout the thickness of the dsisk: Region U, that is Undeformed in torsion (top part – in contact with the fixed punch), Region T, Transition or intermediate region where the shear strain is increasing, and Region S, which is Severely deformed (bottom part in contact with the rotating die) which is uniformly and heavily sheared. The microstructure and Vickers hardness in the three regions show a non-uniform distribution, corresponding to the strain gradient.

  21. Communication

    1. Shape Recovery Kinetics in Vascularized 3D-Printed Polymeric Actuators

      Aditya Balasubramanian and Christopher J. Bettinger

      Article first published online: 19 MAR 2015 | DOI: 10.1002/adem.201500091

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      The shape recovery kinetics of vascularized 3D-printed thermo-responsive shape memory polymeric actuators are measured and compared with predictive models. Experimental and modeled recovery kinetics are in close agreement. A generalizable framework based on predictive models to assess the intrinsic property of SMP that governs the response actuation rate is presented.

  22. Full Papers

    1. Macroscopic Bifurcation and Fracture Mechanism of Polymethyl Methacrylate

      Da Jiao, Rui Tao Qu and Zhe Feng Zhang

      Article first published online: 17 MAR 2015 | DOI: 10.1002/adem.201500021

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      Through deliberately designed experiments, the macroscopic bifurcation and fracture mechanism of PMMA, which is one of important engineering materials, are systematically investigated. The traditional critical stress intensity criterion is found inappropriate for predicting the macroscopic bifurcation. To elucidate the fracture mechanism, a new explanation based on the Ellipse fracture criterion is proposed.

    2. Parameters for Inherently Homogeneous Sintering Processes

      Friedrich Raether

      Article first published online: 17 MAR 2015 | DOI: 10.1002/adem.201400489

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      Thermodynamic driving forces can deteriorate local homogeneity during sintering. Metastable local equilibria during sintering are calculated in voxel-based representative volume elements. Surface diffusion and partially grain growth reduce the driving forces for differential sintering.

    3. High-Throughput Investigation of the Oxidation and Phase Constitution of Thin-Film Ni–Al–Cr Materials Libraries

      Dennis König, Christina Eberling, Michael Kieschnick, Sannakaisa Virtanen and Alfred Ludwig

      Article first published online: 16 MAR 2015 | DOI: 10.1002/adem.201500023

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      Combinatorial materials synthesis and high-throughput characterization is used to investigate the superalloy sub-system Ni–Al–Cr. The investigation focuses on the composition-dependent oxidation behavior of the thin films in the materials library. A thin-film phase diagram is established for the oxidized materials system.

    4. Electron Beam Melting Fabrication of Porous Ti6Al4V Scaffolds: Cytocompatibility and Osteogenesis

      Jia Lv, Zhaojun Jia, Jing Li, Yanen Wang, Jun Yang, Peng Xiu, Ke Zhang, Hong Cai and Zhongjun Liu

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400508

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      Electron beam melting is used in fabrication of porous Ti6Al4V scaffolds with two differing pore sizes. The whole procedure is good in repeatability and accuracy. EBM fabricated porous Ti6Al4V scaffolds can support cell attachment, proliferation and osteogenic differentiation with minimal inflammatory cytokines secretion. The differences in pore structures exert an influence on the biological performance of the porous constructs. The EBMS scaffolds are relatively more biocompatible probably for their larger specific surface area.

    5. Lightweight Metal Cellular Structures Fabricated via 3D Printing of Sand Cast Molds

      Dean Snelling, Qian Li, Nicolas Meisel, Christopher B. Williams, Romesh C. Batra and Alan P. Druschitz

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400524

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      The Binder Jetting additive manufacturing process has been used to fabricate sand molds for casting of lightweight cellular metal structures. Such castings could be used in applications that require lightweight strength, impact absorption, and thermal transfer. A representative octet truss cellular structure was fabricated, modeled using ABAQUS/Explicit software, and compared to experimental quasistatic testing.

  23. Communications

    1. Solid–Solid Phase Transformation During the Reduction of Titanium Dioxide (Anatase) to Produce High-Grade Titanium Powder

      Jeya K. Ephraim and Raj Patel

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400535

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      This is a novel and an innovative methodology for the production of ultra-high pure titanium metal powder from titanium dioxide. A two-step process is being developed for the production of titanium metal which has been a challenge over a century. Figure 2c and 4d clearly reveals that high pure titanium can be produced through solid state reduction route.

  24. Full Papers

    1. Microstructural Features and Mechanical Properties of In Situ Formed ZrB2/Cu Composites

      Zhiguo Zhang, Yinying Sheng, Xiwei Xu and Wei Li

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400532

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      TEM microstructure images of the in situ formed ZrB2/Cu composite shows that the composite consists of hexagonal shaped ZrB2 and Cu matrix. The selected area diffraction indicates that the ZrB2 particles had a hexagonal lattice structure. EDX micro-area signals suggest that a small amount of Zr could dissolve into Cu lattice.

    2. A Cost-Efficient Fabrication Strategy for Conductive Ti2AlC Honeycomb Monolith Using Elemental Powders

      Xuanming Fang, Xiaohui Wang, Hui Zhang, Zhaojin Li, Jialin Li and Yanchun Zhou

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400546

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      A cost-efficient strategy using elemental powders of Ti, Al, and graphite as starting materials is proposed to fabricate conductive Ti2AlC honeycomb monolith by the extrusion method. With direct heating, the shape of the extruded green body was destroyed due to thermal explosion in Ti−Al−C strongly exothermic system. With dwelling during which latent heat released in a controlled manner, Ti2AlC honeycomb monolith with designed structure is obtained, followed by sintering at elevated temperatures.

    3. Influence of the Sulfur Content on the Mechanical Properties of a TRIP/TWIP-Matrix Composite Reinforced with 10 vol% Mg-PSZ

      Sabine Decker, Katja Lange, Tobias Dubberstein and Lutz Krüger

      Article first published online: 11 MAR 2015 | DOI: 10.1002/adem.201400548

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      The study is focused on the influence of an increased sulfur content of the steel-matrix on the microstructure and the mechanical properties under quasi-static compressive deformation of an Mg-PSZ-reinforced TRIP/TWIP-matrix composite. Smaller steel powder particles and, therefore, a fine grained microstructure are formed via gas atomization by increasing the sulfur content. Hence, an increase in strength due to the fine grained steel phase and an improved distribution of the small Mg-PSZ particles within the steel phase is to be expected. However, sulfur precipitates due to a low solubility at the interface between steel and ceramic and deteriorates the mechanical properties.

    4. Joining of Zirconia Reinforced Metal–Matrix Composites by a Ceramics-Derived Technology

      Christian Weigelt, Elisabeth Jahn, Harry Berek, Christos G. Aneziris, Ralf Eckner and Lutz Krüger

      Article first published online: 9 MAR 2015 | DOI: 10.1002/adem.201400559

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      Bulk metal–matrix composites composed of an austenitic stainless steel and magnesia partially stabilized zirconia were prepared via a powder metallurgical processing route with the ceramics-derived extrusion at room temperature. The innovative joining process at room temperature enables joints of various material combinations with mechanical properties under tensile loading at room temperature similar to the base materials.

  25. Communication

    1. Enhanced Synthesis of Metal-Organic Frameworks on the Surface of Electrospun Cellulose Nanofibers

      Elina Laurila, Johannes Thunberg, Stephen P. Argent, Neil R. Champness, Savannah Zacharias, Gunnar Westman and Lars Öhrström

      Article first published online: 9 MAR 2015 | DOI: 10.1002/adem.201400565

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      Carboxyl anchor points enhances Metal organic framework (MOF) formation and distribution on the nanofibers surface. Two methods for introducing carboxyl anchor points on the surface of electrospun cellulose are evaluated. The SEM image (top) show uneven crystal growth on untreated plain cellulose nanofibers. MOF crystals are visible covering the whole nanofiber surface of pretreated electrospun cellulose (bottom). Synthesis of MOF on the surface greatly increases the specific surface area of the nanofiber material.

  26. Full Papers

    1. 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. 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

      Thumbnail image of graphical abstract

      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.

    3. 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

      Thumbnail image of graphical abstract

      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.

    4. 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

      Thumbnail image of graphical abstract

      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.

  27. 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

      Thumbnail image of graphical abstract

      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.

  28. 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

      Thumbnail image of graphical abstract

      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.

  29. 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

      Thumbnail image of graphical abstract

      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.

  30. 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

      Thumbnail image of graphical abstract

      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.

  31. Full Papers

    1. 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

      Thumbnail image of graphical abstract

      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.

    2. 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

      Thumbnail image of graphical abstract

      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.

    3. 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

      Thumbnail image of graphical abstract

      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.

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