Advanced Engineering Materials

Cover image for Vol. 17 Issue 4

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

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  1. 1 - 100
  2. 101 - 114
  1. Full Papers

    1. 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

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      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.

    2. 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.

    3. 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

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      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.

  2. 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

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      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.

  3. 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

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      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. A Single-Crystal Co-Base Superalloy Strengthened by γ′ Precipitates: Structure and Mechanical Properties

      Nikolay Petrushin, Konstantin Hvatzkiy, Victor Gerasimov, Thomas Link, Alexander Epishin, Gert Nolze and Gregory Gerstein

      Article first published online: 20 APR 2015 | DOI: 10.1002/adem.201500088

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      An experimental Co-base superalloy with γ/γ′ microstructure was designed and tested for tension at different temperatures up to 1 000 °C. It was found that this alloy has a much lower yield stress than a similar Ni-base alloy. The supposed reason is less solid solution strengthening due to weaker segregation of refractory elements in the γ matrix.

    4. 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.

    5. 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.

    6. 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.

    7. 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.

  4. 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.

  5. 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.

  6. 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

      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.

  7. 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.

  8. Communication

    1. Monodisperse Polystyrene Foams via Microfluidics – A Novel Templating Route

      Aggeliki Quell, Jonas Elsing, Wiebke Drenckhan and Cosima Stubenrauch

      Article first published online: 19 MAR 2015 | DOI: 10.1002/adem.201500040

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      Microfluidic techniques can be used to generate highly monodisperse polystyrene foams with periodic pore organization. For this purpose, monodisperse foamed emulsions and emulsions, respectively, are to be used as templates. The polymerization of the templates leads to tailor-made polystyrene foams with controllable pore size, pore size distribution, and connectivity.

    2. 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.

  9. 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.

  10. 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.

  11. 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.

    5. Effects of Silver Addition on Critical Current Densities and Mechanical Properties in Bulk MgB2

      Miryala Muralidhar, Kazuo Inoue, Michael R. Koblischka, Akira Murakami and Masato Murakami

      Article first published online: 9 MAR 2015 | DOI: 10.1002/adem.201400583

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      The disk-shaped MgB2 bulk superconducting super-magnets are potential candidates for industrial applications, especially in the medical field. The flux pinning and the mechanical performance of MgB2 bulk superconductors are dramatically improved by adding 4 wt% Ag. The morphology of the Ag particles and their dispersion in the nanoscale can be visualized by SEM and AFM.

  12. 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.

  13. Full Papers

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

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

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

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

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

      Matti Järveläinen, Joonas Humalamäki, Jarmo Laakso and Erkki Levänen

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

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

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

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

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

      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.

    4. 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.

    5. 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.

  14. 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.

  15. 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.

  16. Communications

    1. Flexible, stretchable and weavable piezoelectric fiber

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

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

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

  17. Reviews

    1. Advanced Micro-Lattice Materials

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

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

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

  18. Full Papers

    1. Metallic Braided Structures: The Mechanical Modeling

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

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

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

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

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

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

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

    3. Tuning the Electromechanical Properties of Silicones by Crosslinking Agent

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

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

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

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

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

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

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

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

      Mohammad Shirdel, Hamed Mirzadeh and Mohammad Habibi Parsa

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

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

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

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

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

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

  19. Communications

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

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

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

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

  20. Full Papers

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

      Wolfgang Böhme and Lutz Reissig

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

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

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

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

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

      Thumbnail image of graphical abstract

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

  21. Communications

    1. Soft Actuation of Structured Cylinders through Auxetic Behavior

      Arnaud Lazarus and Pedro M. Reis

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

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

  22. Full Papers

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      Antje Schlieter, I. Shakhverdova and C. Leyens

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

      Paulo Rossi, Sebastian Suarez, Flavio Soldera and Frank Mücklich

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

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

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

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

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

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

  23. Full Paper

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

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

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

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

  24. Full Papers

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

      Yannick Champion and Loïc Perrière

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

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

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

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

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

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

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

      Liyuan Zhao, Huimin Lu and Zhijiang Gao

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

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

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

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

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

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

    5. Self-Assembled Recyclable Hierarchical Bucky Aerogels

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

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

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

  25. Reviews

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

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

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

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

  26. Full Papers

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

      Maryam Mohri, Mahmoud Nili-Ahmadabadi and Julia Ivanisenko

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

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

  27. Communications

    1. Load Sharing Phenomena in Nanoscale Cu/Nb Multilayers

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

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

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

  28. Full Papers

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

      Alberto Fabrizi, Franco Bonollo, Paolo Colombo and Lisa Biasetto

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

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

  29. Communications

    1. Enhanced Plasticity via Kinking in Cubic Metallic Nanolaminates

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

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

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

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

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

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

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

  30. Full Papers

    1. Strain-Induced Phase Transformation of MCrAlY

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

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

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

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

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

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

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

  31. Communications

    1. Novel Adhesion Promoter for Metal–Plastic Composites

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

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

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

  32. Full Papers

    1. A Systematic Approach for the Modeling of Replicated Foams

      Mehrad Mousavi Rahimi and Sharif Shahbeyk

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

      Thumbnail image of graphical abstract

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

  33. Communications

    1. A New Approach to Refine Grains in Al Alloys

      Zhihao Bai, Feng Qiu, Tao Zhang and Qichuan Jiang

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

      Thumbnail image of graphical abstract

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

  34. Full Papers

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

      Xi Lin and Andrew R. Kennedy

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

      Thumbnail image of graphical abstract

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

  35. Communications

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

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

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

      Thumbnail image of graphical abstract

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

  36. Full Papers

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

      Kyle Jiang, Jiran Li and Jian Liu

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

      Thumbnail image of graphical abstract

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

  37. Reviews

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

      Ubaidillah, Joko Sutrisno, Agus Purwanto and Saiful Amri Mazlan

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

      Thumbnail image of graphical abstract

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

  38. Full Paper

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

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

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

      Thumbnail image of graphical abstract

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

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

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

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

      Thumbnail image of graphical abstract

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

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