Advanced Engineering Materials

Cover image for Vol. 9 Issue 11

November, 2007

Volume 9, Issue 11

Pages 931–1017

  1. Cover Picture

    1. Top of page
    2. Cover Picture
    3. Contents
    4. International News
    5. Review
    6. Communications
    1. Cover Picture: In-Situ Synchrotron X-Ray Microtomography Studies of Microstructure and Damage Evolution in Engineering Materials (Adv. Eng. Mater. 11/2007)

      F. Beckmann, R. Grupp, A. Haibel, M. Huppmann, M. Nöthe, A. Pyzalla, W. Reimers, A. Schreyer and R. Zettler

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200790036

      In materials science X-ray microtomography has evolved as an increasingly utilized technique for characterizing the 3D microstructure of materials. The fundamentals of X-ray microtomography experimental methods and the reconstruction and data evaluation processes are briefly described. A review of in-situ synchrotron X-ray microtomography studies in literature is given. Examples of recent work include in-situ microtomography investiagtions of metallic foams, in-situ studies of the sintering of copper particles, and in-situ investigations of creep damage evolution in composites. Future perspectives of in-situ X-ray microtomography studies in materials science are outlined.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. International News
    5. Review
    6. Communications
    1. Contents: Adv. Eng. Mater. 11/2007 (pages 931–934)

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200790034

  3. International News

    1. Top of page
    2. Cover Picture
    3. Contents
    4. International News
    5. Review
    6. Communications
  4. Review

    1. Top of page
    2. Cover Picture
    3. Contents
    4. International News
    5. Review
    6. Communications
    1. In-Situ Synchrotron X-Ray Microtomography Studies of Microstructure and Damage Evolution in Engineering Materials (pages 939–950)

      F. Beckmann, R. Grupp, A. Haibel, M. Huppmann, M. Nöthe, A. Pyzalla, W. Reimers, A. Schreyer and R. Zettler

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700254

      Thumbnail image of graphical abstract

      In materials science X-ray microtomography has evolved as an increasingly utilized technique for characterizing the 3D microstructure of materials. The fundamentals of X-ray microtomography experimental methods and the reconstruction and data evaluation processes are briefly described. A review of in-situ synchrotron X-ray microtomography studies in literature is given. Examples of recent work include in-situ microtomography investiagtions of metallic foams, in-situ studies of the sintering of copper particles, and in-situ investigations of creep damage evolution in composites. Future perspectives of in-situ X-ray microtomography studies in materials science are outlined.

  5. Communications

    1. Top of page
    2. Cover Picture
    3. Contents
    4. International News
    5. Review
    6. Communications
    1. Microcellular Aluminium? – Child's Play! (pages 951–954)

      R. Goodall and A. Mortensen

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700190

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      An innovation (patent pending) in the NaCl-based replication process for the manufacture of microcellular aluminium is presented that overcomes the limitations with the conventional method regarding large pore sizes (because large salt particles are often irregular in shape) and with large sample sizes (because of the long time that is then required for the dissolution step). The method uses a technique used by children to make hardenable modelling paste.

    2. Mechanical Behaviour of Internal Reinforced Aluminium Foams (pages 955–958)

      E. Solórzano, M. A. Rodríguez-Perez, J. A. Reglero and J. A. de Saja

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700180

      Thumbnail image of graphical abstract

      The paper presents a new way to improve the mechanical behaviour of aluminum based foams produced by the powder metallurgical (PM) route; the method is based on the use of internal reinforcements. These reinforcements allow an excellent improvement of the mechanical response in compression, tension and bending all at the same time. The produced samples have showed an excellent reproducibly in their mechanical response.

    3. Inhomogeneous Deformation in Compression – Comparison of Two Bulk-Metallic Glasses (pages 959–962)

      W. H. Jiang, H. F. Zhang, F. X. Liu, Y. D. Wang, H. Choo and P. K. Liaw

      Version of Record online: 15 NOV 2007 | DOI: 10.1002/adem.200700128

      Thumbnail image of graphical abstract

      The mechanical behavior of the work-hardening Cu47.5Zr47.5Al5 bulk-metallic glass in compression was investigated and compared with that of Zr55Ni5Al10Cu30 bulk-metallic glass. Two glassy alloys exhibit substantially different plastic-flow behaviors and shear-band patterns. Cu47.5Zr47.5Al5 displays much smaller inhomogeneity of the plastic deformation both in time and in space than Zr55Ni5Al10Cu30. The work-hardening capability of Cu47.5Zr47.5Al5 may originate from deformation-induced nanocrystallization that may strengthen effectively a shear band.

    4. Microstructure and Mechanical Properties of Directionally Solidified Nb-22Ti-16Si-7Cr-3Al-3Ta-2Hf-0.1Ho Alloy (pages 963–966)

      Y. Tian, G. Cheng, J. Guo, L. Zhou, L. He and H. Ye

      Version of Record online: 15 NOV 2007 | DOI: 10.1002/adem.200700141

      Thumbnail image of graphical abstract

      The attractive combination of properties makes Niobium silicides one of the promising candidates of the next generation materials for high-temperature structural applications. However, the low ductility and toughness of Niobium silicides at room temperature have limited its practical applications. It was recently reported that directional solidification simultaneously improved the mechanical properties as does the addition of Ho. To further improve the strength and ductility of Nbss/Nb5Si3 composites, the authors combined the above-mentioned two benefits into one system.

    5. The Effect of Pre-Processing and Grain Structure on the Bio-Corrosion and Fatigue Resistance of Magnesium Alloy AZ31 (pages 967–972)

      H. Wang, Y. Estrin, H. Fu, G. Song and Z. Zúberová

      Version of Record online: 15 NOV 2007 | DOI: 10.1002/adem.200700200

      Thumbnail image of graphical abstract

      Magnesium alloys are considered as candidate materials for temporary implants. Fatigue resistance and controllable rate of corrosion in bodily fluids are essential for such applications. The effect of the grain structure produced by hot rolling and equal channel angular pressing on the fatigue behaviour and the bio-corrosion rate were studied for alloy AZ31. The results suggest that mechanical processing can be used to control both properties.

    6. Electrochemical Study of AXJ530 Magnesium Alloy Behavior in Alkaline NaCl Solution (pages 973–980)

      S. Amira, A.-M. Lafront, D. Dubé, R. Tremblay and E. Ghali

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700131

      Thumbnail image of graphical abstract

      The corrosion behavior of AXJ530 magnesium alloy has been investigated. Die-cast and thixocast specimens were tested using potentiodynamic polarization, electrochemical noise analysis (ENA), electrochemical impedance spectroscopy (EIS) and immersion tests. These tests showed that all specimens were passive in that solution. However, the passive film formed on thixocast specimens was found to be more protective and resistant to localized corrosion than that of die-cast specimens.

    7. Thermodynamic Investigation of Alkali-Metal-Induced High Temperature Embrittlement in Al-Li Alloys (pages 981–986)

      S. Zhang, Q. Han and Z.-K. Liu

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700183

      Thumbnail image of graphical abstract

      Alkali metals are undesirable impurity elements in aluminum-lithium alloys. Despite their trace amount, they lead to high temperature embrittlement (HTE). In the present work, the results of a thermodynamic investigation are presented to elucidate its mechanism and compared with available experimental data. HTE arises from an intergranular alkali-metal-rich liquid phase that segregates into grain boundaries from the matrix and significantly weakens their strength. A new model is developed to describe the tendency of HTE, which shows grain refinement can decrease the tendency.

    8. Sheet Metal Testing and Flow Curve Determination under Multiaxial Conditions (pages 987–994)

      S. Dziallach, W. Bleck, M. Blumbach and T. Hallfeldt

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700129

      Thumbnail image of graphical abstract

      This study comprises the testing of three auto body steels with regard to formability, tensile strength and forming limits under various stress states. Two multiphase steels (DP600, TRIP700) and one ferritic interstitial free (DX54, 1.0306) were characterised. A further main focus of this study is the comparison of experimentally determined flow curves in the bulge test with extrapolated tensile test flow curves. This comparison gives an insight into the predictability and accuracy of extrapolated curve progressions to higher strain ranges.

    9. The Accurate Determination of Heat Transfer Coefficient and its Evolution with Time During High Pressure Die Casting of Al-9 %Si-3 %Cu and Mg-9 %Al-1 %Zn Alloys (pages 995–999)

      M. S. Dargusch, A. Hamasaiid, G. Dour, T. Loulou, C. J. Davidson and D. H. StJohn

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700189

      Thumbnail image of graphical abstract

      This paper describes the application of a new in-cavity thermal measurement method to determine the interfacial heat transfer coefficient during high pressure die casting of aluminium A380 alloy and the magnesium alloy AZ91D. These measurements enabled the accurate determination of heat flux densities and interfacial heat transfer coefficients and the rapid evolution of these values with time during high pressure die casting of these alloys.

    10. A Rationale for the Acoustic Monitoring of Surface Deformation in Ti6Al4V Alloys during Machining (pages 1000–1004)

      S. Palanisamy, M. S. Dargusch, S. D. McDonald, M. Brandt and D. H. StJohn

      Version of Record online: 15 NOV 2007 | DOI: 10.1002/adem.200700117

      Thumbnail image of graphical abstract

      In this work acoustic monitoring was performed while machining Ti6Al4V with a variety of process parameters. The surface integrity of the components was characterized using microstructural examination and hardness and surface roughness measurements. It is shown that a simple measure of the acoustic spectrum (see figure) can be used to relate operationally induced vibration to the surface integrity of the machined part.

    11. ZrO2-Ni Functionally Graded Joining Interlayers: Microstructure and Properties (pages 1005–1008)

      R. Polanco, P. Miranzo and M. I. Osendi

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700116

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      Functionally graded materials (FGMs) are multi-component composites with a gradual change in composition and/or structure. ZrO2-Ni FGMs in the form of a bonding interlayer with thicknesses in the range 40–100 μm were capable of joining dense ZrO2 pieces (a) or ZrO2 to Ni specimens (b). The number of composition steps in these FGMs was adjusted according to the end joining parts in order to reduce residual stresses. The small formation of Ni7Zr2 at temperatures of 1200 °C favoured the interfacial contact giving a maximum shear stress of 20MPa for the ZrO2/FGM/ZrO2 joints.

    12. Rapid Exponential Convergence of Finite Element Estimates of the Effective Properties of Heterogeneous Materials (pages 1009–1013)

      A. A. Gusev

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700178

      Thumbnail image of graphical abstract

      We develop and validate a general-purpose error estimator for the finite element solutions for the effective properties of heterogeneous materials. We show that the error should decrease exponentially upon increasing order of the polynomial interpolation. We use this finding to demonstrate the practical feasibility of reliable property predictions for a majority of particulate-morphology heterogeneous materials.

    13. Electrical Conducting Behavior of Polyethylene Composites Filled with Self-Passivated Aluminum Nanoparticles and Carbon Nanotubes (pages 1014–1017)

      G. Liang and S. C. Tjong

      Version of Record online: 21 NOV 2007 | DOI: 10.1002/adem.200700145

      Thumbnail image of graphical abstract

      The dielectric and electrical conducting behavior of low density polyethylene (LDPE) composites filled with Al micro- and nanoparticles were investigated. The results show that self-passivated Al particles restrict the formation of conductive pathways within polymer matrices of LDPE/Al micro- and nanocomposites. However, multiwalled carbon nanotube (MWNT) additions promote the electrical conductivity of ternary LDPE/Al/MWNT nanocomposites significantly.

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