Journal of the Japan Society of Powder and Powder Metallurgy
Online ISSN : 1880-9014
Print ISSN : 0532-8799
ISSN-L : 0532-8799
Search
Advanced search
OR
Browse
Search
Volume 59, Issue 12
December
Displaying 1-13 of 13 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Paper
Paper
  • Relation between Critical Temperature and Pseudopotential Radi
    — Elements, AB Compounds, Fe- and Cu-based Compounds —
    Yukio MAKINO, Kazuyoshi YOSHIMURA
    2012 Volume 59 Issue 12 Pages 665-673
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.665
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The relation between the superconducting critical temperature, Tc, and the effective pseudopotential radius, r(eff), was examined for elements, AB-type compounds, and Fe- and Cu-based compounds. Here, assuming arbitrarily their bonding states hybridized with valence electrons, we estimated r(eff) for the materials from the pseudopotential radii given for s, p, and d electrons. It is suggested that Tc can be estimated from the linear relation between Tc and N(v)r(eff)3, where N(v) is the effective number of valence electrons. For the elements with relatively high Tc such as Nb, Tc, and V, for those in AB compounds, and for Cu and Fe in their cuprates, pnictides, and chalcogenides, the value of Tc was found to vary almost linearly to N(v)r(eff)3 by assuming the p3dn or sp2dn hybridization. These findings suggest that the p3dn or sp2dn hybridization is a key bonding character to realize high Tc. For some of the compounds containing transition elements, however, the data deviate largely from the linear relation, indicating that the validity of the present argument is limited in such a category.
    View full abstract
    Download PDF (1094K)
Special Issue: Advances in Sintering Mechanism of Powders and Novel Sintering Technology
Summarization
Paper
  • Investigation of Fine Heterogeneous Microstructure on the Mechanical Properties of MIM Fe-Ni Alloy Steels
    Wan Sharuzi WAN HARUN, Toshiko OSADA, Hyungoo KANG, Fujio TSUMORI, Hi ...
    2012 Volume 59 Issue 12 Pages 677-684
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.677
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The influence of nickel particle sizes, nickel mass%, and sintering temperatures on the microstructure and mechanical properties of injection molded Fe-Ni compacts have been studied. The mixed elemental carbonyl iron and water-atomized nickel powders were utilized in this study. Tempered compact added 6 mass% fine nickel powder which was sintered at 1250°C for 1 hour showed superhigh strength of 2040 MPa with elongation of 8.1 %, the best properties among reported data in MIM low alloy steel compacts. These excellent mechanical properties by fine heterogeneous microstructure of the compact are explained in terms of the complicated networks of nickel content variation throughout the steel matrix.
    View full abstract
    Download PDF (1779K)
  • Effect of Pulse Current Pressure on Sintering of Mg-Al-Zn Elemental Powder Mixtures
    Taku IWAOKA, Mitsuru NAKAMURA
    2012 Volume 59 Issue 12 Pages 685-692
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.685
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    The method of preparing magnesium-sintered alloy using pulsed current pressure and element powders was studied. Aluminum and zinc are general alloying elements for magnesium die casting. The Mg-Al-Zn powder mixtures were prepared by mixing such element powders, and consolidated by pulsed current pressure. The transverse rupture strength of the sintered compacts was influenced by compacting pressure during the increase of temperature. The sintering property of the compacts was estimated by comparing the transverse rupture strength. The transverse rupture strength of the pure magnesium compacts formed at a uniaxial pressure of 10 MPa during heating was about 2.7 times higher than that of 50 MPa. In other words, it is desirable that the compacting pressure is low when the powder mixtures are heated by pulsed current. The transverse rupture strength of the Mg-Al-Zn compacts prepared by this low compacting pressure was compared with that of as-cast.
    View full abstract
    Download PDF (2451K)
Rapid Communication
  • Observation of Reaction Mechanisms for Combustion Synthesis of Co-Al Intermetallic Compounds by Dipping Experiment of Co Wire into Al Melt
    Atsushi HIBINO, Ryutaro KURE
    2012 Volume 59 Issue 12 Pages 693-699
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.693
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In order to analyze the combustion synthesis reactions of Co-Al intermetallic compounds, Co/Al premixed compacts were quenched during the combustion synthesis. Additionally, Co wires were dipped into molten Al, and the compound formation reactions between Co and molten Al were investigated.
    From microstructure observation, SEM-EDX analysis and X-ray analysis of the quenched compacts, molten Al phase, un-reacted Co phase, and CoAl3 intermetallic compound phase were found. The CoAl3 compound phase was also found in the Co wire dipped into the molten Al. The thickness of the CoAl3 compound layer in the dipped wire depended on dipping temperature and dipping time. Therefore, Co-Al intermetallic compounds were formed via CoAl3 formation reaction during the combustion synthesis. Form above results and Co-Al phase diagram, the following reaction equations were suggested in the combustion synthesis of Co-Al intermetallic compound.
    Al(s)→Al(l) (933 K)
    Co(s)+Al(l)→CoAl3(s) (933∼1408 K)
    CoAl3(s)→Co2Al5+(Al-Co) Liq. (1)→CoAl+(Al-Co) Liq. (1) (1408 K∼1453 K)
    Co(s)+(Al-Co) Liq. (1)+CoAl(s) (1453 K∼)
    View full abstract
    Download PDF (1644K)
  • Observation of Reaction Mechanisms for Combustion Synthesis of Mo-Al Intermetallic Compounds by Dipping Experiment of Mo Wire into Al Melt
    Atsushi HIBINO, Katsuyoshi ITOH
    2012 Volume 59 Issue 12 Pages 700-706
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.700
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In order to analyze the combustion synthesis reactions of Mo-Al intermetallic compounds, Mo/Al premixed compacts were quenched during the combustion synthesis. Additionally, Mo wires were dipped into molten Al, and the compound formation reactions between Mo and molten Al were investigated.
    From microstructure observation, SEM-EDX analysis and X-ray analysis of the quenched compacts, molten Al phase, unreacted Mo phase, and MoAl5, MoAl4 intermetallic compound phases were found. These MoAl5 and MoAl4 compound phases were also found in the Mo wire dipped into the molten Al. The MoAl5 phase was synthesized below 1008 K, and MoAl4 phase was formed over 1008 K. Therefore, Mo-Al intermetallic compounds were formed via MoAl5, MoAl4 formation during the combustion synthesis. Form above results and Mo-Al phase diagram, the following reaction equations were suggested in the combustion synthesis of Mo-Al intermetallic compound.
    Al(s)→Al(l) (933 K)
    Mo(s)+Al(l)→MoAl5(s) or Mo(s)+Al(l)→MoAl4(s) (933∼1403 K)
    MoAl4(s)→Mo3Al8+(Al-Co) Liq. (1)
    Mo(s)+(Al-Co) Liq. (1)+Mo3Al8(s)
    View full abstract
    Download PDF (2163K)
Paper
  • Thermodynamic Analysis of Reaction Mechanisms of Mo-Al, Co-Al Intermetallic Compounds by Cylindrical Reaction Model
    Atsushi HIBINO
    2012 Volume 59 Issue 12 Pages 707-713
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.707
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In the previous paper, dipping experiments of metal wires (metal=Mo, Co) into molten Al were investigated to analyze the combustion synthesis of Mo-Al and Co-Al intermetallic compounds. From the dipping experiment, it was found that MoAl4 and CoAl3 compound layers were formed between the metal wires (Mo, Co) and the molten Al. The compound formation reactions were analyzed by a cylindrical reaction model that the outer side was the molten Al, central cores were the metal wires(Mo, Co), and intermediate layers were the intermetallic compounds(MoAl4, CoAl3).
    The compound formation reactions were able to be simulated by calculating the cylindrical model. The values calculated by the model agreed with the experimental value. The following reaction parameters were obtained from the model calculation for the Mo-Al system.
    LogDAl/m2·s−1=−9.813×102/T−10.243
    Logkc/mol·m−2·s−1=−9.696×102/T−1.755
    It was suggested that the reaction rate was controlled by the diffusion process of Al and the chemical reaction process, from the reaction resistances calculation using the cylindrical model. Additionally, the numerical analysis by the cylindrical model was performed for Co-Al system.
    View full abstract
    Download PDF (1583K)
Review
  • Trend in Development of Diamond Particle Dispersed Metal Matrix Composites
    Kiyoshi MIZUUCHI, Kanryu INOUE, Yasuyuki AGARI, Masakazu KAWAHARA, Yuk ...
    2012 Volume 59 Issue 12 Pages 714-720
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.714
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    In order to fabricate high-performance thermal management materials with ultra-high thermal conductivities and low CTEs, we have recently initiated a series of investigations, where metal-matrix composites (MMCs) containing high thermal conductive fillers were uniquely fabricated. In our study, to avoid the damage of filler particle surfaces, spark plasma sintering (SPS) processing was used as a processing technique. In the present review, thermal properties of diamond particle dispersed MMCs fabricated using SPS process in our recent works are introduced in comparison with those produced using various fabrication techniques by other researchers.
    View full abstract
    Download PDF (1304K)
  • Multi-scale Modeling of Sintering Mechanics
    Fumihiro WAKAI
    2012 Volume 59 Issue 12 Pages 721-727
    Published: December 15, 2012
    Released on J-STAGE: January 23, 2013
    DOIhttps://doi.org/10.2497/jjspm.59.721
    JOURNAL OPEN ACCESS
    Show abstractHide abstract
    Many sintering bodies shrink in an anisotropic manner when the particle packing is not isotropic. In the continuum mechanics frame work, macroscopic shrinkage in sintering is described as a linear function of the sintering stress tensor and the viscosity tensor. These macroscopic quantities are determined rigorously from local microstructure and microscopic kinetics involving grain boundary diffusion. The shrinkage is driven by the hydrostatic component of the sintering stress tensor, while the anisotropic deformation is driven by its deviatoric components. This model is able to predict both the evolution of the anisotropic microstructure during sintering, and also the effect of the local microstructure on anisotropic shrinkage.
    View full abstract
    Download PDF (1525K)
JSPM Announcements
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top