Advanced Engineering Materials

Cover image for Vol. 7 Issue 11

November, 2005

Volume 7, Issue 11

Pages 975–1056

    1. Cover Picture: Recent Developments in Nanostructured Materials (Adv. Eng. Mater. 11/2005)

      C. Suryanarayana

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200590022

      An overview of recent developments in nanostructured materials is presented. After providing a brief introduction to the synthesis, consolidation, and properties of nanostructured materials, the review focuses on recent attempts to simultaneously achieve high strength and ductility in these materials and also the recent successes in molecular dynamics simulation studies to understand their mechanical properties. Approaches such as bimodal distribution of grain sizes, low-temperature/high strain-rate deformation, introduction of heavy twinning, and in-situ consolidation methods have been explained. The review concludes with a description of the potential applications of nanostrucutred materials for hydrogen storage, coatings, and in energetics.

    2. Recent Developments in Nanostructured Materials (pages 983–992)

      C. Suryanarayana

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500135

      An overview of recent developments in nanostructured materials is presented. After providing a brief introduction to the synthesis, consolidation, and properties of nanostructured materials, the review focuses on recent attempts to simultaneously achieve high strength and ductility in these materials and also the recent successes in molecular dynamics simulation studies to understand their mechanical properties. Approaches such as bimodal distribution of grain sizes, low-temperature/high strain-rate deformation, introduction of heavy twinning, and in-situ consolidation methods have been explained. The review concludes with a description of the potential applications of nanostrucutred materials for hydrogen storage, coatings, and in energetics.

    3. Metastable Beta Titanium Alloys for Orthopedic Applications (pages 993–998)

      J. I. Qazi and H. J. Rack

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500060

      This article provides an overview of metastable β titanium alloys either being utilized or being considered for use in orthopedic applications. The effects of thermomechanical processing on the mechanical properties (e.g., elastic modulus, tensile, wear and high cycle fatigue performance) of Ti-15Mo-0.2O, Ti-12Mo-6Zr-2Fe (TMZF), Ti-29Nb-13Ta-4.6Zr and Ti-35Nb-7Zr-5Ta are reviewed. The osteointegration behavior of Ti-29Nb-13Ta-4.6Zr and Ti-35Nb-7Zr-5Ta-O alloys is also presented.

    4. Biomimetic Bonelike Composites and Novel Bioactive Glass Coatings (pages 999–1004)

      A. P. Tomsia, E. Saiz, J. Song and C. R. Bertozzi

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500143

      There is an increasing need for better and more durable orthopedic implants. A short-term solution is the modification of current implant surfaces to enhance their osseointegration but in the long term new implant materials should be developed. This paper reviews recent work on the fabrication of bioactive glass coatings to enhance implant osseointegration and the latest research on the development of novel organic-inorganic composites specifically designed for bone replacement.

    5. Biomolecular Structure Prediction Stochastic Optimization Methods (pages 1005–1009)

      A. Schug, B. Fischer, A. Verma, H. Merlitz, W. Wenzel and G. Schoen

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500141

      Biomolecular structure prediction remains an important challenge to biophysical chemistry. We recently developed an all-atom free energy forcefield (PFF01) for protein structure prediction with stochastic optimization methods. We review recent studies, which demonstrated all-atom folding of several proteins and summarize recent progress for in-silico high-throughput screening strategies for rational drug design, which are also based on the use of stochastic optimization methods to determine the conformation of the receptor-ligand complex.

    6. The First Observation of a Shear-Induced bcc[RIGHTWARDS ARROW]fcc Transformation in Nanocrystalline Ferrite (pages 1011–1014)

      Y. Ivanisenko, I. MacLaren, R.Z. Valiev and H.-J. Fecht

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500152

      Ferrite has been transformed to austenite at room temperature in an initially pearlitic steel. This occurs under high shear strain conditions once the alloy has been grain-refined down to a nanoscale dimensions by high-pressure torsion deformation. This transformation must have occurred by a martensitic mechanism and plays the role of an additional deformation mechanism for the nanostructured material.

    7. Polymer/NiTi-composites: Fundamental Aspects, Processing and Properties (pages 1014–1023)

      K. Neuking, A. Abu-Zarifa, S. Youcheu-Kemtchou and G. Eggeler

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500130

      NiTi shape memory alloys can be used as actor materials and perform mechanical work; they can also be used for damping applications. In combination with polymers their functionality can be increased. Shape memory effects of NiTi alloys are associated with large strains and in a NiTi/polymer-composite, the polymer can accommodate these large strains without breaking. In a NiTi/polymer-composite the polymer can for example be used to store elastic energy, to provide corrosion resistance or to assist in a damping application. For all applications, a good bonding between the shape memory alloy and the polymer is required. The present paper considers fields of applications, processing and properties of NiTi/polymer-composites.

    8. Controllable Work Function of Li:Al Alloy Nanolayers for Organic Light-Emitting Devices (pages 1023–1027)

      Y. Kim, D. Choi, B. Moon, E. Oh, H. Lim, S. Kwon and C. Ha

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500151

      The surface of Li:Al nanolayers that were deposited by thermal evaporation of Li:Al alloy sources has been measured by ultraviolet photoelectron spectroscopy, which exhibited huge variation with the Li:Al nanolayer thickness. The hybrid organic light-emitting devices with the controlled Li:Al nanolayer surface contacts as an electron-injecting layer showed linearly varied charge transport and turn-on voltages with the work function of the nanolayer surfaces.

    9. Dynamic Strain Ageing During Stress Relaxation in Selected Magnesium Alloys Containing Rare earth Elements (pages 1027–1032)

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

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500132

      Three magnesium alloys containing rare earth were deformed at room temperature and above room temperature at various strain rates. Stress relaxation tests were performed in order to study dynamic strain ageing phenomena effects. Different manifestations of strain ageing were observed. Non-monotonous temperature and strain rate dependence of the flow stress were observed. Post relaxation effect, i.e. an increase of the flow stress at the beginning of plastic deformation after stress relaxation in comparison to the flow stress at the beginning of stress relaxation, was detected.

    10. Multilayer Ni-P Coating for Improving the Corrosion Resistance of AZ91D Magnesium Alloy (pages 1032–1036)

      C. Gu, J. Lian and Z. Jiang

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500136

      The purpose of this paper is to provide a high corrosion resistance multilayer coating on AZ91D magnesium alloy. The multilayer coating having a thickness of about 45 μm and consisting of different Ni-P alloy layer was prepared by electroless deposition. The composition of the multilayer coating from substrate to surface was designed as the protective layer, a Ni-P layer with high phosphorus content and a Ni-P layer with low phosphorus content, respectively. The so-called protective layer was a direct electroless plating Ni-P deposits with the thickness of about 10 μm. The electrochemical behavior and the corrosion resistance of this multilayer coating were evaluated by the electrochemical measurement and the acid immersion test, respectively. Being different from the other Ni-P alloys coatings on the magnesium alloy, this multilayer coating could provide the electrochemical protection for the substrate.

    11. Identification of Silicon Agglomerates in Quenched Al-Si Hypereutectic Alloys From Liquid State (pages 1037–1043)

      F. C. Robles Hernández and J. H. Sokolowski

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500137

      The study of Al-Si hypereutectic alloys in the liquid state can be conducted in quenched samples, which allows the identification of microscopic particles known as Si agglomerates that transform into the well known primary Si particles at the liquidus temperature. The understanding of the nature of the Si agglomerates is the key to determine the exact conditions to refine the microstructure and particularly the primary Si from the liquid or semi-solid states.

    12. Three-dimensional Silica Fiber Reinforced Silicon Nitride-based Composites Fabricated via Different Polysilazanes (pages 1043–1046)

      G. Qi, C. Zhang, H. Hu, F. Cao, S. Wang and Y. Jiang

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500104

      Three-dimensional silica fiber reinforced silicon nitride-based composites were fabricated at 873–1073 K in ammonia using polyhydriomethylsilazane and perhydropolysislazane, respectively. The composites showed high weight pickups during repeated pyrolysis cycles, non-brittle failure behavior with fiber pull-out in the fracture surfaces and high flexural strength of 114.5 and 144.9 MPa. It was the good state of silica fibers, controlled fiber/matrix interfaces and dense ceramic matrix that contributed to the high strength of the composites.

    13. Thermal Shock Damage of a 3D-SiC/SiC Composite (pages 1046–1049)

      S. Wu, L. Cheng, L. Zhang and Y. Xu

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500092

      Thermal shock of a three-dimensional (3D) SiC/SiC composite prepared by chemical vapor infiltration (CVI) process was conducted using water quenched method. Thermal shock damage of the composite was assessed by SEM characterization and measurement mechanical properties using three-point flexure after quenching. After quenched from 1200°C to 25°C water for 100 cycles, the composite retained 80% of the original flexural strength in the longitudinal direction while cracked through the width direction. Thermal shock damage of the composite was analyzed by thermal stress analysis based on the braiding structure of the composite as well as the distribution and shape of flaws referred to residual pores in the matrix. The braided structure and the dimension difference resulted in the anisotropy of mechanical properties and the matrix pores configuration of the composite, which led to the thermal shock damage anisotropy of the composite.

    14. High Strength Lead-Free Composite Solder Materials using Nano Al2O3 as Reinforcement (pages 1049–1054)

      X. Zhong and M. Gupta

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500109

      High strength light weight lead-free composite solder materials containing varying amount of nano-alumina particulates were synthesized by powder metallurgy process employing different extrusion temperatures. The presence of nano Al2O3 particulates not only enhanced strength and improved dimensional stability but also reduced the weight of the solder alloy matrix. Fairly uniform distribution of the nano-alumina particulates was observed in the composites.

    15. Applications of Phase-sensitive X-Ray Imaging to the Structural Analysis of Composite Laminate High-performance Sail Fabrics (pages 1054–1056)

      L. Tesei, G. Tesei, L. Mancini, G. Tromba and F. Zanini

      Version of Record online: 28 NOV 2005 | DOI: 10.1002/adem.200500142

      High-performance sail fabrics cannot be studied with conventional X-ray imaging set-ups because of their low absorption, while other techniques do not give a full insight of the inner structure of the material. We show preliminary results of the application of phase-contrast X-ray imaging to the study of modern laminate sailcloth.

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