Advanced Engineering Materials

Cover image for Advanced Engineering Materials

May, 2004

Volume 6, Issue 5

Pages 273–349

    1. Contents: Adv. Eng. Mater. 5/2004 (pages 273–276)

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200490003

    2. Fatigue of Magnesium Alloys (pages 281–289)

      C. Potzies and K.U. Kainer

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400021

      Magnesium alloys show a high specific strength and are therefore increasingly used for light-weight constructions in the transportation industry. Vibrations of moving vehicles lead to cyclic loading in the applied component. To predict the behaviour of the material under the influence of cyclic loading and to fully apply the potential weight reduction, it is vital to understand the fatigue behaviour of magnesium alloys.

    3. Established and Emerging Materials for use as High-Field Magnet Conductors (pages 290–297)

      K. Spencer, F. Lecouturier, L. Thilly and J.D. Embury

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400014

      Conductor materials for use in high-field pulse magnets require a demanding combination of high strength and high conductivity. Three different approaches to designing such materials are reviewed, with each approach focusing on different length scales. New perspectives are given on each alternative with regard to the fabrication, mechanical and electrical properties.

    4. Nanostructured High-Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes (pages 299–303)

      J.-W. Yeh, S.-K. Chen, S.-J. Lin, J.-Y. Gan, T.-S. Chin, T.-T. Shun, C.-H. Tsau and S.-Y. Chang

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200300567

      A new approach for the design of alloys is presented in this study. These “high-entropy alloys” with multi-principal elements were synthesized using well-developed processing technologies. Preliminary results demonstrate examples of the alloys with simple crystal structures, nanostructures, and promising mechanical properties. This approach may be opening a new era in materials science and engineering.

    5. Hypereutectic Al-Si Binary Alloys Prepared by Melt Spinning Method (pages 303–306)

      Z.K. Zhao, J.C. Li and Q. Jiang

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200300578

      Five quenched Al-Si alloys with different compositions have been manufactured and whose properties and structures are determined. The results show that the alloys consist of supersaturated α-Al nanocrystals, amorphous matrix and primary Si. When 30 %<CSi %<40 %, there is more than 50 % amorphous phase. Crystallization of the amorphous phases and Si separation from the supersaturated α-Al nanocrystals occur as temperature increases.

    6. Conditions for Hot Rolling of Iron Aluminide (pages 307–310)

      P. Kratochvíl and I. Schindler

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200300575

      Hardening and softening processes determine the hot rolling workability of iron aluminide. Mathematical model enable to predict the mean equivalent stress, which depends on strain, strain rate and temperature, and to choose the proper rolling conditions. The ordering (ferite A2 [LEFT RIGHT ARROW] intermetallic B2) influences the ease of the rolling process.

    7. A New Approach for Rapid Annealing of Medium Carbon Steels (pages 310–313)

      Y. Zhang, C. He, X. Zhao, C. Esling and L. Zuo

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400013

      The kinetic effects of high magnetic field on the solid-state phase transformation during cooling in medium carbon steel are investigated. Imposing of a 14-Tesla magnetic field has promoted the proeutectoid ferritic transformation from austenite, and resulted in uniform and refined microstructure of ferrite and pearlite even under rapid cooling. Insight into the rapid magnetic annealing process contributes to the development of new heat-treatment techniques with high productivity.

    8. Tailoring Titanium Hydride Decomposition Kinetics by Annealing in Various Atmospheres (pages 313–330)

      D. Lehmhus and G. Rausch

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200300572

      With series production of aluminium foams according to the Fraunhofer process a reality, further improvement of structural homogeneity has gained interest. Since this characteristic is strongly influenced by blowing agent decomposition, means to adapt the latter have been investigated: The paper concentrates on thermal treatment of TiH2, comparing effects induced by treatment time, temperature and atmosphere variation. Structural characteristics of AlSi7 foams using TiH2 variants as foaming agent are evaluated.

    9. Microstructure and Properties of an HfB2-SiC Composite for Ultra High Temperature Applications (pages 331–336)

      F. Monteverde and A. Bellosi

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400016

      An ultra-high-temperature ceramic (UHTC) based on HfB2 was produced. The microstructure consisted of fine and regular diboride grains (2 μm average size), with SiC particulate distributed intergranularly, not rarely in clustered formation, and low levels of secondary phases were identified. The resulting thermo-mechanical properties proved interesting results for microhardness and fracture toughness. The microstructural alteration experienced within the explored temperature range renders the material unsuitable for service in extreme conditions of temperature and pressure.

    10. Silicoaluminum Carbonitride with Anomalously High Resistance to Oxidation and Hot Corrosion (pages 337–340)

      L. An, Y. Wang, L. Bharadwaj, L. Zhang, Y. Fan, D. Jiang, Y. Sohn, V.H. Desai, J. Kapat and L.C. Chow

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400010

      Due to their excellent thermal and mechanical properties silicon-based ceramics and composites are prime candidates for high temperature structural applications. In this communication the authors report for the first time that amorphous silicoaluminum carbonitride (SiAlCN) ceramics possess anomalously high resistance to oxidation and hot-corrosion. A mechanism underlying the observed phenomena is discussed.

    11. SiC Foams Produced by Gel Casting: Synthesis and Characterization (pages 340–343)

      R. Mouazer, I. Thijs, S. Mullens and J. Luyten

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200400009

      SiC foams were fabricated by gelcasting with a commercially available powder and agar as gelling agent. Ceramic foams processed by gel casting have dense struts and are therefore mechanically stronger than foams produced by the conventional poly-urethane replica method. First, special attention was given to the preparation and characterization of the powder suspension using silicon carbide powders which has been recognized as a high performance material.

    12. Engineered Stress-Profile Silicate Glass: High Strength Material Insensitive to Surface Defects and Fatigue (pages 344–349)

      V.M. Sglavo, A. Prezzi and T. Zandonella

      Version of Record online: 24 MAY 2004 | DOI: 10.1002/adem.200300509

      A modified ion-exchange process can be used for the production of high strength glass, which is, in addition, insensitive to surface flaws. In such ESP-Glasses (Engineered Stress Profile) the residual stress profile possesses a maximum compression at a certain depth from the surface, which, conversely, is almost stress free. Such unusual stress profile allows a stable and controlled growth of surface defects before final catastrophic failure. In this way the strength can be independent from the size of pre-existing surface flaws in a certain range of crack size and possess limited scatter. In the present work, three commercial silicate glasses have been used for the production of ESP glass.