Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 73, Issue 10
Displaying 1-10 of 10 articles from this issue
  • Naoki Ogasawara, Teiko Okazaki, Chihiro Saito, Yasubumi Furuya
    2009 Volume 73 Issue 10 Pages 759-763
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      Giant magnetostrictive Fe-Pd and Fe-Ga alloys are promising as actuator/sensor materials with high respective velocity and stress created by magnetostriction. To apply them to a micro valve, we developed magnetostrictive actuators, that is, Fe80Ga20/Ni and Fe70.4Pd29.6/Ni bimorph layers. These cantilever-type actuators can be bent by applying magnetic field parallel to length. An actuator point displaced about 270 μm under a low magnetic field of 37 kAm-1. Large (20 mm×18 mm×0.2 mm) and small (17.5 mm×5 mm×0.2 mm), (10 mm×3 mm×0.2 mm) actuators were applied to a micro-gas valves. The opening and closing action of a valve consisting of magnetostrictive bimorph layers can be controlled remotely by magnetic fields. Gas flow rate can be driven from 43 to 0 ml min-1 by increasing the magnetic field to 20 kAm-1. The response time to the applied magnetic field is below 0.12 s. Moreover, the magnetostrictive actuator is excellent in durability.
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  • Keiyu Nakagawa, Teruto Kanadani, Yasuyuki Mori, Yuto Ishii
    2009 Volume 73 Issue 10 Pages 764-767
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      The effects of the jetting temperature of the melting alloy on the ribbon thickness of rapidly solidified Fe75Si10B15 and Fe79.5Si8.5B12 alloys were examined. The rapidly solidified Fe75Si10B15 and Fe79.5Si8.5B12 alloy ribbons' mean thickness decreased continuously with the increased jetting temperature. However, the temperature dependence of the ribbon thickness in the Fe79.5Si8.5B12 alloy was greater than that of the Fe75Si10B15 alloy.
       The results demonstrate that the viscosity of liquid Fe-Si-B systems alloys influences the ribbon thickness. Moreover, when the contact conditions between the rotating roll comes and puddle are good, then the ribbon thickness decreases.
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  • Tomohiro Yoshimura, Hisashi Imai, Katsuyoshi Kondoh
    2009 Volume 73 Issue 10 Pages 768-772
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      Titanium (Ti) alloys are applied to various products used in the aircraft, automotive and motor cycles industries due to their high specific strength. Ti-6Al-4V (Ti64) is one of the most general Ti alloys, and shows superior mechanical properties i.e. density of 4.43 g/cm3 and tensile strength over than 900 MPa. However, its application is limited because of a poor plastic formability and the expensive raw materials.
       In this study, Roll-Compaction (RCP) process was applied to fabricate high strength pure titanium composite reinforced with titanium oxides (TiO2) by using cheap sponge Ti powders as input materials. RCP was effective to improve the mechanical responses by the grain refinement and the in-situ formation of TiO2 dispersions of the matrix. RCPed powder was consolidated by using spark plasma sintering (SPS) process to serve a high density compact. Subsequently, hot extrusion process was applied to the sintered billet to prepare a full density rod specimen. The evaluation of their mechanical properties at room temperature showed high tensile strength of 640 MPa and good elongation of 17%.
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  • Mikito Ueda, Yasutaka Ta, Toshiaki Ohtsuka, Hidenori Takahashi
    2009 Volume 73 Issue 10 Pages 773-777
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      To reduce Mg content in Al-Mg alloy for aluminum recycling, calcined powder made from used dry-cell battery was reacted with the liquid aluminum alloy. The powder was found to consist of ZnMn2O4, MnO, ZnO, and carbon by XRD analysis. After the reaction between pellets of the powder and the alloy in liquid at 973 K or 1073 K for 3.6×103 s, Mg content in the alloy decreased from 4.0 to 2.3 mass%. And at the same time, contents of Mn and Zn in the alloy increased from 0 to about 0.2 and 0.1 mass%, respectively. During the reaction, metallic Mg in the liquid Al-Mg alloy was found to move in to the pellets to form MgO. It may be assumed that an exchange reaction between Zn2+ at ZnO in the pellets and Mg2+ from the liquid alloy takes place.
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  • Manako Tanaka, Masahiro Kitada
    2009 Volume 73 Issue 10 Pages 778-785
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      The metallurgical microstructure and mechanical properties of the steel barrel of a Japanese matchlock gun fabricated in the Edo period have been investigated. The purpose of this work is to obtain modern materials-science data of the Japanese matchlock gun and to study the manufacturing technique of the steel barrel. Test pieces are cut from the center, the muzzle and the screw of the barrel. The carbon concentration is determined by chemical analysis. The metallurgical microstructure and nonmetallic inclusions of the barrel are observed using an optical microscope and a scanning electron microscope (SEM). Test pieces for measuring the mechanical properties are cut from the gun. To evaluate the hardness, Vickers hardness (Hv) is used. The stress-strain curve, tensile strength and elongation of the gun are obtained.
       The carbon concentration is 0.01∼0.1mass% for the center of the barrel, 0.04∼0.1 mass% for the muzzle of the barrel, 0.05∼0.5 mass% for the front sight (Saki-meate in Japanese) and 0.13∼0.3 mass% for the male screw. The distribution of nonmetallic inclusions in the center and in the muzzle of the barrel suggest that the barrel was fabricated by a manufacturing technique called Udonbari (in Japanese). The metallurgical microstructure of the specimen taken from the muzzle of the barrel in the vertical direction suggests that the barrel and a front sight were joined mechanically. Both male and female screws were made by a cutting technique. The tensile strength and elongation are 316∼366 MPa and 25.0∼31.4%, respectively.
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  • Jee-Wook Lee, Katsunari Sasaki, Joseph D. Ferrara, Kiyoshi Akiyama, To ...
    2009 Volume 73 Issue 10 Pages 786-793
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      Two-dimensional quantitative analysis of point focus X-ray beam diffraction was performed using a transmission optics system to examine the biological apatite (BAp) orientation in the femurs of an osteopetrotic (op/op) mouse and a normal mouse. The Mo Kα (wavelength: 0.07107 nm) was used as characteristic X-ray radiation as a substitute for conventional Cu Kα (wavelength: 0.15418 nm) radiation. At first a theoretical calculation concerning with X-ray absorption and peak resolution was performed, and subsequently X-ray diffraction measurements were carried out to confirm the usefulness of the transmission X-ray method by Mo Kα radiation. The distribution of the preferential orientation of the BAp c-axis was finally measured and calculated as an integrated intensity ratio of (002)/(310) in a plane roughly containing the bone longitudinal axis. The result resembled analysis from a conventional reflection X-ray diffraction method by Cu Kα radiation but this transmission optics system was more convenient for the screening of BAp orientation in bones without sectioning.
       The distribution of the preferential alignment of the BAp c-axis was measured as a function of the longitudinal axis in the femurs of a 12-week mutant op/op mouse and a littermate control mouse. The preferential alignment of the BAp c-axis along the longitudinal direction is much lower in the op/op mouse than in the control mouse in all analytical positions. The transmission optics system using Mo Kα radiation in this study provides a fuss-free method for analyzing BAp orientation as a bone quality parameter.
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  • Kenichi Nakajima, Osamu Takeda, Takahiro Miki, Tetsuya Nagasaka
    2009 Volume 73 Issue 10 Pages 794-801
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      Currently, several metals are commercially recycled from by-products and wastes by metallurgical processing. However, the metallurgical process has each characteristic, which causes limitation for resource recovery. The combinations of elements in secondary resources, such as by-products and wastes, are often different from those in natural resources. There are even combinations that are not present in natural resources. Conventional metallurgical processes have been optimized for economical and efficient extraction of desired elements only from large amount of ores under constant grade. Therefore, in order to extract metals from secondary resources by the conventional metallurgical process, it is necessary to estimate the recoverability of the constituent elements by taking into account their chemical properties well in advance. In particular, analysis for combination of elements is significantly important.
       In this study, we developed the evaluation method of metal resources recoverability based on thermodynamic analysis, and made clear the element distribution among gas, slag and metal phases during metal recovery based on thermodynamic analysis. In an application of the method shows that Cu, and precious metals (Ag, Au, Pt, Pd) present in mobile phones can be recovered as metals in the pyrometallurgy process of Cu in a converter. Other elements distributed in the slag phase are difficult to recover. The result of our analysis reflects the trends observed in the distribution of metals in copper metallurgy, thereby indicating the validity of our proposed evaluation method.
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  • Makoto Hasegawa, Tsuyoshi Endo, Hiroshi Fukutomi
    2009 Volume 73 Issue 10 Pages 802-808
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      In order to understand the effect of microstructural change in bond coat (BC) layer on interfacial mechanical properties, heat treatment in a vacuum was performed in air plasma-sprayed thermal barrier coating system (APS-TBCs). TBC layer, BC layer and substrate were composed of 8 mass% Y2O3 partially stabilized ZrO2, NiCoCrAlY alloy and Inconel 738 Nickel base superalloy, respectively. Heat treatments were performed at 1413 K for 10 and 50 hours. Microstructural observation of TBCs was done from the transverse section of the specimens. Under the as-sprayed condition, the BC layer consists of a fine mixture of β and γ′ phases. The size of the both phases increased with the increase in heat treatment time. β phase near the BC/substrate interface disappeared during the heat treatment. This may be due to the diffusion of Al from the BC layer to the substrate and diffusion of Ni from substrate to BC layer. Yield stress of the BC layer decreased and interface delamination strain energy release rate Γi increased with the increase in the heat treatment time. The increase of Γi may be attributed to the increase of the size of the process zone ahead of the delamination front due to the decrease in yield stress of BC layer.
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  • Shinji Koyama, Issei Oya
    2009 Volume 73 Issue 10 Pages 809-815
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      The effect of formic acid surface modification on the bond strength of the solid-state bonded interface of tin has been investigated by SEM observations of the interfacial microstructures and fractured surfaces. Formic acid surface modification was carried out by boiling a tin surface (finished by electrolytic polishing) in formic acid for 750 s. Solid-state bonding was carried out in a vacuum chamber at a bonding temperature Tj of 383-453 K and a bonding pressure Pj of 7 MPa (bonding time=1.8 ks). Because of surface modification, bonded joints were obtained at a bonding temperature that was ~50 K lesser than the typical temperature required, and the bond strength was comparable to that of the base metal. When the joint strength was much lower than the base-metal strength, a number of fine inclusions were found to be distributed in the interfacial region. As the joint strength increased with bonding temperature, these inclusions were coarsened, and their distribution density decreased. The increase in joint strength with bonding temperature corresponded well with the observed change in the size and density of the inclusions.
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  • Kwang Sub Chi, Yong Hee Kim, Jae Sik Yoon, Shoji Goto, Byung Il Kim
    2009 Volume 73 Issue 10 Pages 816-821
    Published: 2009
    Released on J-STAGE: October 01, 2009
    JOURNAL FREE ACCESS
      Hot-dip galvannealed sheet (GA) were developed from the automotive industry. It has high strength of 590 MPa grade in tensile strength. However, in order succeeds from automobile industry, the microstructure and galvannealing behavior of galvannealed TRIP steel sheets must be strictly controlled. The metal where the silicon content is high has problems with weld-ability, zinc coating and reduction of retained austenite volume fraction after galvannealing process. The main purpose of this study is to solve the problem as indicated above.
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