Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
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Volume 75, Issue 6
Displaying 1-6 of 6 articles from this issue
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Regular Articles
  • Impact Analysis of Copper Price on Copper Scrap Recovery
    Kengo Kawahara, Ichiro Daigo, Yasunari Matsuno, Yoshihiro Adachi
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 327-331
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.327
    JOURNAL FREE ACCESS
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      Recently, copper price reached the highest level ever. It is expected that the rise of copper price becomes a strong incentive for recovering copper scrap from end-of-life products. Therefore, in this paper, we aimed to analyze the relation between copper price and the amount of recovered copper scrap in Japan. A dynamic material flow analysis (MFA) of copper was conducted to estimate the amount of copper discarded in the end-of-life products during 1980-2008 in Japan. It was found that the recovery rates of copper scrap have risen with the increase in copper price, especially after 2003. A multiple linear regression model was adopted to explain the amount of recovered copper scrap during these three decades, in which copper price, the amount of copper discarded in the end-of-life products, etc. played important roles.
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  • Estimation of Kinetic Parameters for Combustion Synthesis of FeAl Intermetallic Compound by Dipping Experiment of Fe Wire into Al Melt
    Atsushi Hibino
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 332-340
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.332
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      The reaction rate for the formation of Fe-Al intermetallic compounds was examined by dipping experiment of Fe wire into Al melt in the temperature range between 973 K and 1373 K, to determine the kinetic parameters of combustion synthesis of FeAl. A piece of Fe wire and Al powder were put into an alumina crucible, and vacuum-sealed in a quartz tube. The tube was held in an electric furnace to promote the compound formation reaction. A microstructure observation and SEM-EDX analysis of the dipped Fe wire were performed. It was found that the compound formation reaction occurred at the interface between the molten Al and the Fe wire, and a cylindrical Fe2Al5 layer was formed in the wire. The thickness of the formed layer depended on the holding time and the dipping temperature. The reaction process has been similar to the combustion synthesis of FeAl intermetallic compound. Therefore, the kinetic parameters could be determined by the dipping experiment. The experimental data have been analyzed using a cylindrical model which took into account the diffusion process of Al in the Fe2Al5 compound layer and chemical reaction process on the interface between Fe2Al5 and Fe. The diffusion coefficient, DAl and the reaction rate constant, kc were estimated. The curves were calculated by using the obtained kinetic parameters and were in satisfactory agreement with the experimental values.
    log10 DAl/m2•s−1=−1887/T−8.369
    log10 kc/mol•m−2•s−1=−3177/T+1.839
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  • Formation Mechanism of Cu-Enriched Zone in the Interdendritic Regions of Primary β-Sn in Sn-1.0Ag-0.5Cu Alloy
    Yoshiko Takamatsu, Hisao Esaka, Kei Shinozuka
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 341-347
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.341
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      In this study, the solidification process has been investigated to clarify the formation mechanism of Sn-Cu6Sn5 binary eutectic structure after growth of primary β-Sn in undercooled Sn-1.0Ag-0.5Cu alloy by using thermal analysis, interruption tests and energy dispersive X-ray spectroscopy. First Cu-enriched zone was formed around β-Sn after growth of primary β-Sn, then the Cu-enriched zone changed into a round shape as the temperature decreased. Eventually some spherical Cu-enriched droplets, which were 10 µm in diameter, were separated from the remained liquid. The concentration of Cu and Ag in the remained liquid was higher than the expected value from equilibrium phase diagram since the considerably large volume fraction of β-Sn nucleated in this study. Moreover, Cu was piled-up around β-Sn with the growth of β-Sn.
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  • Tensile Properties in Electrodeposited Nanocrystalline Ni-W Alloy
    Kazutaka Fujita, Taiji Suidu, Tohru Yamasaki
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 348-354
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.348
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      Nanocrystalline Ni-W alloy specimens containing 16.9 at% W with about 20 μm in thickness, 50 μm in width and 4 mm in parallel part length were produced by using both UV photolithography and electrodeposition methods. The average grain size was about 6 nm in diameter. The tensile test was conducted at a strain rate of 1.4×10−4 s−1. The nominal tensile strength and Young's modulus were about 2.8 GPa and about 125 GPa with or without polishing, respectively. The elastic strain and plastic strain on the polished specimen were about 1.9% and 0.76%, respectively and those on the non-polished specimen were about 1.9% and 0.49%, respectively. The true tensile strength on the polished and non-polished specimens were 3.8 GPa and 3.4 GPa, respectively. In addition, the stress-strain curve showed work hardening. The macroscopic fracture part yielded necking and the microscopic fracture surface showed dimple pattern.
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  • The Improvement of Mechanical Properties of Metallic Foams by Carbonates as a Foaming Agent
    Takuya Koizumi, Kota Kido, Kazuhiko Kita, Koichi Mikado, Svyatoslav Gn ...
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 355-360
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.355
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      Metallic foams are commonly produced using hydride foaming agents. Carbonates are safer to handle than hydrides; furthermore a fine and homogenous cell structure can be obtained in the powder metallurgy route. In this study, the effects of mass fraction of magnesium carbonate and dolomite as a foaming agent on cell structure and mechanical properties of the foams were investigated. Dolomite gave more fine and homogenous cell structure than magnesium carbonate. Average cell size of the foam by dolomite was twenty times less than that of the foam by TiH2. The dolomite-foam showed higher plateau stress than the TiH2-foam; therefore, dolomite-foam has high energy absorbing capability.
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  • Tie-Lined Compositions of the σ and (γ, δ) Phases in the Re-Cr-Ni System at 1573 K
    Shigeru Saito, Toshiyuki Takashima, Katsumi Miyama, Kazuya Kurokawa, T ...
    Article type: Regular Article
    2011 Volume 75 Issue 6 Pages 361-365
    Published: 2011
    Released on J-STAGE: June 10, 2011
    DOIhttps://doi.org/10.2320/jinstmet.75.361
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      Compositions with tie-lines between the σ and (γ, δ) phases in a ternary Re-Cr-Ni system were investigated at 1423 K by heat-treating various ternary Re-Cr-Ni alloys in vacuum for times up to 2000 h. The microstructures of the Re-containing alloys which had been water-quenched after various heating times were observed and their concentration profiles for Re, Cr and Ni were measured using an electron probe micro-analyzer. The Re-Cr-Ni alloys consisted of the σ phase with either the γ or δ phase. It was found that concentration profiles of the γ phase became flat after short heat treatment, but longer times of up to 2000 h were required to achieve the same effect for the σ and δ phases.
      The tie-lined compositions(at%) of the each phase at 1573 K were experimentally determined as follows. The σ phase tie-lined with the γ phase(17.3Re, 20.6Cr and 62.1Ni) consists of 53.1Re, 25.5Cr and 21.4Ni. The σ phase tie-lined with the γ phase(16.9Re, 19.2Cr and 63.9Ni) consists of 53.0Re, 24.6Cr and 22.4Ni. The σ phase tie-lined with the γ phase(12.7Re, 24.8Cr and 62.5Ni) consists of 48.4Re, 30.9Cr and 20.7Ni. The σ phase tie-lined with the γ phase(6.1Re, 46.2Cr and 47.7Ni) consists of 28.1Re, 52.3Cr and 19.6Ni. The σ phase tie-lined with the δ phase(85.6Re, 5.2Cr and 9.2Ni) consists of 61.1Re, 27.7Cr and 11.2Ni.
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