Advanced Engineering Materials

Cover image for Vol. 9 Issue 5

May, 2007

Volume 9, Issue 5

Pages 335–423

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
    1. Cover Picture: Microstructural Comparison of Conventional and Microwave Sintered BaTiO3 (Adv. Eng. Mater. 5/2007)

      A. Dorner-Reisel, S. Schöps, A. Lenk and G. Schmutzler

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200790012

      Microwave sintering has a profound effect on the sintering progress and, subsequently, on the microstructure of BaTiO3 ceramics. Under the influence of the electromagnetic field, sintering in a monomode microwave cavity (2.45 GHz, 1.5 kW) starts earlier. XRD points out that at room temperature, the tetragonal phase is more stable in the conventional sintered samples than in the microwave sintered barium titanate. Raman spectroscopy indicates a reduction of the Curie temperature of microwave sintered BaTiO3 in comparison to the conventional processed electroceramic.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
  3. Guide for Authors

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
  4. International News

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
  5. Research News

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
    1. Ordered Arrays of Nanostructures and Applications in High-Efficient Nano-Generators (pages 343–348)

      Y. Lei, Z. Jiao, M. Wu and G. Wilde

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700084

      Thumbnail image of graphical abstract

      Large-scale ordered nanostructure arrays on substrates, including nanodots, nano-holes, nanowires and nanotubes, can be fabricated using template fabrication processes. The controllable structural parameters and properties of the ordered nanostructure arrays make them quite suitable to be used in many device-related application areas.

  6. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Guide for Authors
    5. International News
    6. Research News
    7. Communications
    1. Surface Tension and Viscosity of the Ni-based Superalloy CMSX-4 Measured by the Oscillating Drop Method in Parabolic Flight Experiments (pages 349–354)

      K. Higuchi, H.-J. Fecht and R. K. Wunderlich

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600277

      Thumbnail image of graphical abstract

      The surface tension and the viscosity of the Ni-based superalloy CMSX-4 were measured by the oscillating drop method on electromagnetically levitated specimen under reduced gravity conditions on a parabolic flight. The twenty seconds of reduced gravity available in a single parabola proved sufficient for melting, heating into the stable liquid and free cooling to solidification.

    2. Superlightweight Nanoengineered Aluminum for Strength under Impact (pages 355–359)

      H. Zhang, J. Ye, S. P. Joshi, J. M. Schoenung, E. S. C. Chin, G. A. Gazonas and K. T. Ramesh

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700015

      Thumbnail image of graphical abstract

      A hierarchically designed Al-5083 composite achieves dramatic mechanical properties at impact rates of deformation through a combination of three micro-structural length scales: strengthening through a nanocrystalline core architecture and through length-scale dependent reinforcement with μ-sized ceramic particles, and enhanced ductility through the incorporation of a certain volume fraction of microscale grains (see fig.).

    3. Cellular Titanium by Selective Electron Beam Melting (pages 360–364)

      P. Heinl, A. Rottmair, C. Körner and R. F. Singer

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700025

      Thumbnail image of graphical abstract

      Cellular titanium combines the excellent properties of compact titanium with the extraordinary properties of cellular structures. The production of cellular titanium based on standard techniques is associated with various difficulties. In this paper, the fundamental principles of the Selective Electron Beam Melting technique and two different approaches to generate cellular titanium structures are described. As predicted by theory, the relative density, the elastic modulus and the compressive yield strength of the different structures are correlated.

    4. Adapting Titanium Implants to the Elasticity of Bone by Comparison of Spring Stiffness (pages 365–369)

      G. Hohenhoff, H. Haferkamp, A. Ostendorf, O. Meier, S. Ostermeier and M. Schimek

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600241

      Thumbnail image of graphical abstract

      The aim of adapted endoprostheses is to achieve at least the same percentage of negative elongation under the same stress in an implant-bone-combination. The negative elongation is like the downward deflexion of a spring under pressure. Due to the limitations mentioned above, the comparison of spring stiffness of bone and implant is the most promising way to achieve the adapted implant elasticity aimed at.

    5. Stress Relaxation in AX41 Magnesium Alloy Studied at Elevated Temperatures (pages 370–374)

      Z. Trojanová, P. Lukác and K. U. Kainer

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700018

      Thumbnail image of graphical abstract

      The article presents the deformation behaviour of a Mg-Al-Ca alloy (AX41) deformed at elevated temperatures. Stress relaxation tests were used to determine internal and effective components of the applied stress. Apparent activation volume decreases with the increasing effective stress. The values of the activation volume are in the order of tens b3. The main thermally activated process is very probably the dislocation glide in non-basal planes.

    6. Positional Control of Superparamagnetic Iron Oxide Nanoparticles in Silica Beads (pages 375–380)

      B. Steitz, F. Krauss, S. Rousseau, H. Hofmann and A. Petri-Fink

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700052

      Thumbnail image of graphical abstract

      The inverse microemulasion synthesis of silica-beads loaded with up to 40% superparamagnetic iron oxide nanoparticles is reported. Positional control of the nanoparticles in the bead is achieved by stabilizing the SPIONs by either polyvinyl alcohol (PVA) or citric acid, which results in the distribution of the SPIONs on the surface or inside the beads, respectively.

    7. Synthesis and Characterization of Alumina Microtubes in a Template Process from Short Carbon Fibers (pages 381–384)

      Z. Pajkic and M. Willert-Porada

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700056

      Thumbnail image of graphical abstract

      A novel, two step process for synthesis of Al2O3 microtubes from short carbon fibers as templates is reported. In the first process step, the carbon fibers are coated with a Al-AlN-Al4C3 composite in a microwave plasma fluidized bed CVD process. The coated material is then being treated in a furnace on high temperature in air, resulting finaly with alumina microtubes (hollow fibers).

    8. Composed Mullite Substrates for the Development of Crystalline Silicon Solar Cells (pages 385–388)

      F. M. M. Snijkers, J. van Hoolst, M. Schoeters, E. Alvarez, J. M. Matamala and J. J. Luyten

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600283

      Thumbnail image of graphical abstract

      Composed mullite substrates ware manufactured by laminating green tape of high purity mullite on top of kaolin-based sintermullite tapes. The sinter shrinkages were tuned in order to make co-sintering possible. The lamination process parameters and the sintering behavior of both tapes were studied. Two-layer green tapes were sintered to dense ceramic sheets, of which the micro-structure was investigated with FESEM.

    9. Depth-Sensing Indentation Hardness Characterization of HfC-Based Composites (pages 389–392)

      S. Guicciardi, L. Silvestroni, G. Pezzotti and D. Sciti

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600202

      Thumbnail image of graphical abstract

      The hardness of two HfC-MoSi2 composites was characterized by depth-sensing tests. At low peak loads, the hardness of the constituent phases was measured while at high loads the hardness was attributed to the bulk composites. By considering indentation size effects and composite rules, the experimental values of the composites were compared to the theoretical expectations calculated with the hardness of the constituent phases.

    10. Residual Stress Investigation in SiC/MoSi2(p) Composites (pages 393–399)

      D. Sciti, S. Guicciardi, G. Celotti, M. Deluca and G. Pezzotti

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600233

      Thumbnail image of graphical abstract

      Thermal residual stresses in SiC matrix – MoSi2 reinforced composites were investigated by Raman microprobe spectroscopy and X-ray diffraction. The introduction of 10 and 30 vol% MoSi2 particles generated compressive stresses in the SiC matrix, with magnitude of about –80 and –190 MPa, respectively. A typical residual stress map obtained through Raman spectroscopy for the SiC-30 vol% MoSi2 composite is shown in the accompanying figure.

    11. Microstructural Comparison of Conventional and Microwave Sintered BaTiO3 (pages 400–405)

      A. Dorner-Reisel, S. Schöps, A. Lenk and G. Schmutzler

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200600276

      Thumbnail image of graphical abstract

      Microwave sintering has a profound effect on the sintering progress and, subsequently, on the microstructure of BaTiO3 ceramics. Under the influence of the electromagnetic field, sintering in a monomode microwave cavity (2.45 GHz, 1.5 kW) starts earlier. XRD points out that at room temperature, the tetragonal phase is more stable in the conventional sintered samples than in the microwave sintered barium titanate. Raman spectroscopy indicates a reduction of the Curie temperature of microwave sintered BaTiO3 in comparison to the conventional processed electroceramic.

    12. Measurement of the Debonding Resistance of Strongly Adherent Thick Coatings on Metals via In-plane Tensile Straining (pages 406–412)

      S. Ryelandt, L. Delannay, R. Persoons, K. Van Acker and F. Delannay

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700014

      Thumbnail image of graphical abstract

      When the ratio hc/hs of coating and substrate thicknesses is large enough, interfacial debonding can be induced to propagate from the root of a transverse crack under in-plane loading. An energy balance analysis accounting for the flow rule of the substrate allows translating the load for steady state debonding into an upper bound for the debonding toughness. The method is validated by FEM simulations using a cohesive zone model.

    13. Oxidation resistant aluminized MCrAlY coating prepared by Spark Plasma Sintering (SPS) (pages 413–417)

      D. Oquab, C. Estournes and D. Monceau

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700012

      Thumbnail image of graphical abstract

      NiCoCrAlYTa single and multi layered coatings on an AM3® nickel base superalloy have been fabricated by Spark Plasma Sintering (SPS). MCrAlY powder and Al foil were sintered on the superalloy in a single run SPS experiment The results reported in this paper open the way to faster development of new high temperature coatings with complex structure and composition.

    14. Ti and Ti-6Al-4V Coatings by Cold Spraying and Microstructure Modification by Heat Treatment (pages 418–423)

      W.-Y. Li, C. Zhang, X. Guo, J. Xu, C.-J. Li, H. Liao, C. Coddet and K. A. Khor

      Version of Record online: 18 MAY 2007 | DOI: 10.1002/adem.200700022

      Thumbnail image of graphical abstract

      Microstructure characteristics of cold sprayed Ti and Ti-6Al-4V coatings and the effect of post-spray heat treatment on their microstructure were examined. Results showed that the as-sprayed coatings presented a porous structure but with the deposition efficiency of more than 60% depending on the spray conditions. After annealing the porosities of Ti and Ti-6Al-4V coatings were apparently increased. A sound metallurgical bonding between the contact interfaces of deposited partilces was formed through atom diffusion during annealing.

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