Advanced Engineering Materials

Cover image for Vol. 8 Issue 11

Special Issue: Materials Science & Engineering

November, 2006

Volume 8, Issue 11

Pages 1023–1177

Issue edited by: H. Clemens, G. Dehm, C. Mitterer

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Reviews
    5. Communications
    6. Essay
    1. Cover Picture Adv. Eng. Mater. 11/2006

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200690022

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Reviews
    5. Communications
    6. Essay
    1. Contents: Adv. Eng. Mater. 11/2006 (pages 1023–1028)

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200690021

  3. Reviews

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Reviews
    5. Communications
    6. Essay
    1. Mechanical Size-Effects in Miniaturized and Bulk Materials (pages 1033–1045)

      G. Dehm, C. Motz, C. Scheu, H. Clemens, P. H. Mayrhofer and C. Mitterer

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600153

      Interfaces and surfaces can impose mechanical size-effects on materials. The deformation mechanisms become constrained when microstructural and/or geometrical dimensions decrease. This effect can improve, e.g. the creep resistance of a bulk lamellar material, but it may cause failure for a miniaturized material component due to high internal stresses. Several dislocation mechanisms causing size-dependent flow stresses are addressed and the current understanding of size-effects in miniaturized and bulk materials is reviewed.

    2. The Limits of Refinement by Severe Plastic Deformation (pages 1046–1056)

      R. Pippan, F. Wetscher, M. Hafok, A. Vorhauer and I. Sabirov

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600133

      Heavy plastic deformation at low temperatures – usually called severe plastic deformation – results in decrease of the size of grain like structural elements. At very large deformation this refinement reaches saturation. The paper reviews the effect of processing parameters on the minimum size, which can be obtained by severe plastic deformation in single phase as well as in multiphase alloys.

    3. Self-organization of Nanostructures in Inorganic and Organic Semiconductor Systems (pages 1057–1065)

      C. Teichert, C. Hofer and G. Hlawacek

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600142

      Semiconductor nanostructures – and in particular ensembles of them – are the prerequisites for the ongoing miniaturization in microelectronics. Since lithographic techniques become increasingly expensive and technologically complex, self-organization into quasiperiodic nanostructure arrays is an elegant alternative. Here, strain-induced pattern formation in SiGe/Si(001), ion bombardment induced self-organization of inorganic semiconductors, and crystallite ordering in oligophenylene films are presented as illustrative examples for nanostructure self-organization that is not at all restricted to semiconductor systems.

    4. Precipitation Behaviour of a Complex Steel (pages 1066–1077)

      H. Leitner, M. Bischof, H. Clemens, S. Erlach, B. Sonderegger, E. Kozeschnik, J. Svoboda and F. D. Fischer

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600165

      Nanometer-sized precipitates in tool steels are the most important microstructural constituents determining the mechanical and thermophysical properties. For the improvement of existing steel grades and the development of new tool steels a fundamental knowledge of the precipitation reactions during heat treatments and at application temperature is of vital interest. Thus, a comprehensive characterization of the various precipitates is required. This paper reviews the studies performed on a complex tool steel which hardens by secondary hardening carbides and intermetallic phases using advanced methods for characterizing nm-sized precipitates

  4. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Reviews
    5. Communications
    6. Essay
    1. The Characterization of Local Deformation and Fracture Properties – a Tool for Advanced Materials Design (pages 1079–1083)

      O. Kolednik

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600150

      Novel experimental techniques have been recently developed to measure local deformation and fracture properties. The techniques comprise quantitative fracture surface analysis and in-situ loading experiments in combination with digital image analysis. Examples are presented, demonstrating how these methods can be used to investigate the damage evolution in materials, to improve tools for the numerical simulation, and for the design of more fracture resistant materials and components.

    2. In-Situ X-ray Diffraction as a Tool to Probe Mechanical Phenomena Down to the Nano-Scale (pages 1084–1088)

      J. Keckes, E. Eiper, K. J. Martinschitz, P. Boesecke, W. Gindl and G. Dehm

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600156

      Several applications of laboratory and in-situ synchrotron X-ray diffraction (XRD) techniques to characterize mechanical phenomena in nano-scale structures are presented. A size dependency of the flow stress in Al thin films is studied by non-ambient XRD. Moreover, a recovery of the modulus of cyclically strained coir fibres is analysed by in-situ XRD combined with mechanical tests.

    3. Characterization of Residual Stresses in Compressor Discs for Aeroengines (pages 1088–1092)

      U. Cihak, P. Staron, M. Stockinger and H. Clemens

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600145

      Thermal residual stresses in a forged compressor disc and in a thin model plate evolving during water-quenching were investigated. The thermal residual stresses were calculated by finite element simulation and verified by neutron diffraction. Furthermore, the heat transfer coefficient was examined by temperature measurements during cooling. It was found that the residual stress state and the temperature can only be reflected satisfactorily with a temperature-dependent heat transfer coefficient.

    4. Microstructure and Mechanical Properties of a C/C-Cu Joint Developed for Plasma Facing Components (pages 1092–1096)

      E. Eidenberger, C. Scheu, G. Hawranek, R. Pippan, B. Schedler, H. Leitner and H. Clemens

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600162

      In the interface region of C/C-Cu joints different microstructures are developed dependent on the amount of wetting agent employed during fabrication. Two C/C-Cu Joints containing different amounts of wetting agent were investigated by SEM and XRD measurements. Elemental maps were created to further determine the distribution of the occurring phases. To determine the fracture toughness of the samples 3-point bending tests were performed and the fracture surfaces were examined. The two samples show different crack paths which can be related to the found microstructures.

    5. Metallurgical Aspects of Casting High-Manganese Steel Grades (pages 1096–1100)

      G. Gigacher, R. Pierer, J. Wiener and C. Bernhard

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600152

      The high temperature strength and internal crack susceptibility of a high Mn-steel grade, X50MnAl 25 1 has been compared to that of a HSSS steel and that of two low carbon steels. High strength and crack susceptibility are supposed to be limiting factors in casting high-Mn steels on conventional continuous casting machines.

    6. Microstructure and Texture Formation during Hot Rolling of Niobium-Rich γ TiAl Alloys with Different Carbon Contents (pages 1101–1108)

      A. Stark, A. Bartels, R. Gerling, F.-P. Schimansky and H. Clemens

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600127

      Three γ-TiAl alloys with a base composition of Ti-45Al-7.5Nb (at.%) and different carbon contents were used for hot rolling experiments at temperatures in the upper range of the (α+γ) phase field. The formation of the microstructure as well as the texture evolution of γ- and α-phase are analysed at various as-rolled and annealed states. The texture of the α-Ti(Al) phase exhibits components probably resulting from co-deformation with the γ-TiAl phase.

    7. Numerical Modelling of Kinking in Lamellar γ-TiAl Based Alloys (pages 1109–1113)

      T. Schaden, F. D. Fischer, H. Clemens, F. Appel and A. Bartels

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600238

      Processing of titanium aluminides often starts with the break-down of the coarse-grained lamellar microstructure of the ingot. The lamellar colonies consist of alternating layers of γ-TiAl and α2-Ti3Al. The goal of this study is to investigate which local effects are responsible for the observed global softening of the material.

    8. Functional Properties of Wires and Thin Ribbons of Several Shape Memory Alloys (pages 1113–1118)

      A. C. Kneissl, E. Unterweger and G. Lojen

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600144

      The so-called two-way shape memory effect could be very attractive for technical applications. This work deals with the generation of a two-way shape memory effect and its optimization in NiTi, NiTiW and CuAlNi wire material. Moreover, thin ribbons of CuAlNi have been produced by melt-spinning to investigate the shape memory behaviour of small parts for possible applications as microsensors and microactuators.

    9. Determination of Mechanical Properties of Copper at the Micron Scale (pages 1119–1125)

      D. Kiener, C. Motz, T. Schöberl, M. Jenko and G. Dehm

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600129

      Using a focused ion beam workstation, micron-sized bending and compression samples were fabricated from a pure copper single crystal. The bending and compression experiments exhibited a strong size effect on the flow stress of copper, reaching values in the order of 1 GPa for the smallest test structures. Conventional strain gradient plasticity approaches are not capable of explaining this behaviour. The surface damage introduced by Ga+ ion implantation during focused ion beam preparation was investigated using Auger electron spectroscopy and its consequence on the mechanical response of the miniaturized test samples is addressed.

    10. High-Temperature Tribological Behavior of CrN-Ag Self-lubricating Coatings (pages 1125–1129)

      K. Kutschej, C. Mitterer, C. P. Mulligan and D. Gall

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600131

      The CrN-Ag coating system is a promising candidate for high-temperature lubrication, as it combines the wear and corrosion resistance of CrN with the lubrication properties of Ag. In this study, special emphasis is laid on the influence of surface reactions, like the formation of Ag agglomerates and/or surface oxidation, and on the high-temperature tribological behavior at 600 °C. Characterization of the friction curves and the wear tracks provides an understanding of the relation between the out-diffusion of Ag (forming agglomerates) and its lubricating effect.

    11. Oxide Fiber Composites with Promising Properties for High-Temperature Structural Applications (pages 1129–1134)

      R. A. Simon and R. Danzer

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600149

      This paper summarizes the mechanical properties of recently developed Oxide Fiber Composites (OFCs) consisting of high-strength continuous oxide fibers embedded in an oxide matrix. The OFCs exhibit a favorable combination of high strength and damage tolerance due to unusual homogeneous microstructures. The tensile behavior in both fiber- and matrix-dominated loadings and interlaminar shear behavior are described. Special emphasis is placed on the attractive thermal shock resistance and high-temperature long-term performance of these new materials.

    12. Thermography and Simulation of Advanced Nonlinear ElectroCeramic Components (pages 1134–1139)

      A. Platzer, P. Supancic and R. Danzer

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600155

      In usage active nonlinear electroceramic PTC components are heated by Joule selfheating. The heating rate is accelerated by a positive feedback effect and leads to large temperature differences in the components, which cause large mechanical stresses and may even cause a catastrophic failure of the component. Amplitude and shape of these fields sensitively depend on material parameters, geometry, initial and boundary conditions. Even very small geometry changes can shift the region of maximum temperatures from the centre to the edge of the component. Thermography turned out to be an excellent method to determine local and transient temperature fields, is used to evaluate results of model calculations and to determine local materials properties (e.g. the electric resistance).

    13. Influence of Annealing on the Fracture Behavior of 200 μm Thick α-PVDF Films (pages 1140–1145)

      G. M. Wallner, Z. Major, G. Maier and R. W. Lang

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600130

      For 200 μm thick, extruded α-PVDF films it has been shown that annealing affects the mechanical and the fracture behavior. The subtle distinctions in microstructure reflected by differential scanning calorimetry and X-ray scattering methods are associated by significant differences in the plastic deformation and fracture mechanisms.

    14. Fatigue Crack Growth and Process Zone Development in a PE-HD Pipe Grade in Through-Thickness Direction (pages 1146–1150)

      W. Balika, G. Pinter and R. W. Lang

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600137

      The fatigue crack growth behaviour of a high density polyethylene (PE-HD) pipe grade was characterized using a method based on a linear elastic fracture mechanics (LEFM) approach. The development of the crack front and the front of the process zone ahead of the crack was examined in the thickness direction of the specimen. The experimental data are employed to determine the effective crack length by compliance relationships.

    15. Atomistic Modeling of Optical Properties of Thin Films (pages 1151–1155)

      P. Puschnig and C. Ambrosch-Draxl

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600128

      It is shown how the combination of ab-initio electronic structure methods with simulations based on the macroscopic Maxwell theory can be used to compute the optical properties of thin layered media. We apply the theory to a thin film of para-hexaphenyl, which is a promising canditate for organic electro-optical semiconductor devices, and obtain results in excellent agreement with experimental observations.

    16. Microwave Studies of Photonic Crystals (pages 1156–1161)

      F. Kuchar, R. Meisels, P. Oberhumer and R. Gajic

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600136

      Experimental and numerical investigations on photonic crystals with millimeter dimensions and the lowest photonic bands in the microwave range are reported. Negative refraction, right-handed and left-handed behavior of the modes in the photonic crystal and the effect of positional disorder are analyzed.

    17. Thermodynamic Modeling of High-Temperature Fe-Ni-Heazlewoodite (pages 1161–1164)

      P. Waldner and W. Sitte

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600132

      The thermodynamic modeling of key sub-systems as the iron-nickel-sulfur system is a contribution to the development of extended databases for multicomponent metal-sulfur systems. A further extension of a recent thermodynamic modeling of the Fe-Ni-S system is presented. A two-sublattice approach in the framework of the Compound Energy Formalism is used for a consistent integration of a second ternary high–temperature heazlewoodite phase within a complete thermodynamic description of the Fe-Ni-S system.

    18. Wet or Dry – Hardness, Stiffness and Wear Resistance of Biological Materials on the Micron Scale (pages 1164–1169)

      T. Schöberl and I. L. Jäger

      Version of Record online: 16 NOV 2006 | DOI: 10.1002/adem.200600143

      The present paper reports on the influence of humidity on hardness and stiffness measurements of biological materials. For the first time abrasion tests on the micrometer-scale were performed on human dentin and enamel and, moreover, on tools of non-vertebrates. Hardness and modulus can depend strongly on the water content; large differences can appear between wet samples measured under fluid or in air.

  5. Essay

    1. Top of page
    2. Cover Picture
    3. Contents
    4. Reviews
    5. Communications
    6. Essay