Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
Volume 40, Issue 12
Displaying 1-15 of 15 articles from this issue
  • Makoto INOUE, Osamu TANNO, Yo KOJIMA
    1990 Volume 40 Issue 12 Pages 879-884
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    The production of high purity magnesium was carried out by vacuum sublimation method. The apparatus for vacuum sublimation was constructed and the operation condition was investigated using commercial grade magnesium and magnesium alloy AM100 as volatile substances. The vacuum sublimation was effective for the separation of aluminum, manganese, copper and silicon. While the deposite of 99.99 mass% magnesium was not obtained by using commercial grade magnesium. The separation of zinc was sufficient at the condense portion of high temperature side. When vacuum sublimation was carried out for magnesium alloy AM100, the deposit of 99.99 mass% magnesium was obtained. The corrosion resistance of deposited magnesium obtained from magnesium alloy AM100 was superior to that of the other deposited magnesium.
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  • Yoshiki TSUNEKAWA, Hirohiko YOSHIDA, Masahiro OKUMIYA, Itaru NIIMI
    1990 Volume 40 Issue 12 Pages 885-890
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    Aluminum matrix composites preforms containing silicon carbide whiskers (SiCw) were fabricated by reactive low pressure plasma spraying, to form aluminum nitrides (AlN) in the plasma flame. SiCw distribution was nearly uniform in the sprayed preform. The alignment of SiCw in the preform was improved from 3-dimensional to planar random by hot-forging at 873K with 196MPa. However, the average length of SiCw, which was 15μm as recieved, was shortened to 6μm through the processing. Reactive low pressure plasma spraying gave a formation of approximately 2vol% AlN, as a secondary reinforcement, with chamber pressure of 13.3kPa. The hot-forged hybrid MMCs showed higher tensile strengths compared to those without AlN. Aluminum powder size affected the SiCw distribution in the sprayed preform, and also finer matrix powder was of advantage to forming more AlN and strengthening the MMCs. Reactive low pressure plasma spraying with nitrogen and hydrogen mixed plasma gas contributed to more AlN formation due to higher plasma flame temperature. Such an improved processing for strengthening can be applied to aluminum alloy matrix composites.
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  • Hajime KATO, Tatsumi TOZAWA, Yoshimasa TAKAYAMA
    1990 Volume 40 Issue 12 Pages 891-895
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    A dry wear test was carried out for a couple of specimens (stator: AZ31 magnesium alloy, rotor: S50C carbon steel) with a Ohgoshi-type quick wear testing machine at room temperature. In this study, sliding distance was kept constant, namely, 200m, sixteen sorts of sliding speeds were adopted within the sliding speed range of 0.058m/s to 3.62m/s and three sorts of loads were applied. Influence of load and sliding speed on wear loss, sliding surface temperature, view of wearing surface and so on was invesitigated for AZ31 magnesium alloy. The main results obtained were as follows; (1) The value of wear loss reduced with the increment of sliding speed and showed a minimum one nearly at a critical sliding speed. After that, the value of wear loss tended to increase gradually as sliding speed bacame higher. (2) The value of wear loss apparently increased within the higher sliding speed range as load was high, while there was hardly observed the influence of load on wear loss within the lower sliding speed range. (3) The rise in the sliding surface temperature with the increase of load was not clear at the lower sliding speeds below a critical one. But after the sliding speed exceeded a critical one, the sliding surface temperature clearly became higher with the increment of sliding speed and/or load. (4) Wearing mode changed from abrasive wear to adhesion wear as sliding speed increased. This was assumed to result from the softening phenomenon of AZ31 magnesium alloy due to the rise in the sliding surface temperature.
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  • Yasuhiro UETANI, Sadayuki ABOU, Shizuo TADA, Susumu IKENO
    1990 Volume 40 Issue 12 Pages 896-902
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    A polycrystalline aluminum with the average grain size of 120μm was deformed in tension mode to 0.01% strain. The behavior of slip bands formed on each grain surface was investigated by optical microscopy as well as crystallographic orientation determined by SEM-ECP method. Some grains in which secondary slip systems had been activated were observed at this stage of plastic deformation. None of elastic strain incompatibility, transmission factor Nij and plastic strain incompatibility could explain the secondary slip systems becoming active in such grains. When the secondary slip system produced more similar shape change to that of the surrounding grains than the primary slip system did, the secondary slip system was understood to become preferentially active, taking account of the two-dimensional surface shape change after small plastic deformation.
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  • Osami SERI
    1990 Volume 40 Issue 12 Pages 903-905
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    The occurence of pitting attacks in Al-Mn alloys were investigated by using "pitting factor". The pitting factor for the Al-Mn alloys galvanic-coupled with pure iron in deaerated 0.1M NaCl solution decreased with increasing manganese content in Al-Mn alloys. The pitting factor was smaller than 1 when the manganese content in Al-Mn alloy was higher than 1.62%. This leads to the no-occurence of pitting attacks for aluminum.
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  • Taichi KAMIJO, Akihiko FUJIWARA, Yoshiyuki YONEDA
    1990 Volume 40 Issue 12 Pages 906-910
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    The rolling and recrystallization textures of the aluminum single crystals with the (123) [634] orientation were examined by the ordinary X-ray pole figure technique. The initial orientation was sharply maintained as the main component of the rolling texture up to the highest 99% reduction. The orientation spread shown by the iso-intensity lines below level 1 increased with an increase in the rolling reduction. The formation of the deformation structure of a rotated cube orientation and the symmetrical component of the initial orientation with respect to the transverse direction were detected in the specimen of the highest reduction. The recrystallization textures were mainly composed of the rotated cube orientation after cold-rolling more than 95%. None of the other seven variants were observed. Thus, the rotated cube texture in aluminum single crystals with the stable orientation was concluded to be formed by the preferential nuclsation from the deformation structure near (001) [100] orientation.
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  • Shigeru AOKI, Mitsuo NIINOMI, Toshiro KOBAYASHI
    1990 Volume 40 Issue 12 Pages 911-917
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    Hydrogen embrittlement of Al-Li-Cu-Mg-Zr alloys hydrogenated by cathodic charging was investigated using a three point bending test at various strain rates and temperatures. Embrittlement was observed together with planner slipped fracture surface by short time hydrogenation. The marked embrittlement was observed at a certain strain rate and temperature range. The lattice constant was found to be maximum at the region about 0.1mm inside from the specimen side surface just after hydrogenation, where the hydrogen concentration was taken to be maximum. The amount of hydrides on the specimen surface seemed to increase by hydrogenation. The variations of hydrogen embrittlement zone (HEZ) ratio with crosshead speed and temperature were similar to those of the reduction ratio of total absorbed energy (rt) with crosshead speed and temperature.
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  • Susumu IKENO, Sadayuki ABOU, Shizuo TADA, Yasuhiro UETANI
    1990 Volume 40 Issue 12 Pages 918-924
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    Slip bands formed at lower strain region ranged from 0.01 to 2% in polycrystalline aluminum were investigated by optical microscopy and crystallographic orientation analysis using a SEM-ECP method. Many of grains exhibited slip bands caused by the primary slip system at 0.01% strain. Half of them produced new additional slip bands caused by the secondary slip system with increased plastic deformation. While, some grains showing slip bands formed by the secondary slip system alone at the initial stage of plastic deformation (0.01% strain) produced slip bands due to the primary slip system with further plastic deformation. Short slip bands were frequently observed at 2% strain near the grain boundaries. The slip system of this slip bands had very small Schmid factor. The phenomenon of this slip system becoming active could not be explained by the several theories proposed for the bicrystal deformation.
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  • Akira KITAHARA, Shigeru AKIYAMA, Hidetoshi UENO
    1990 Volume 40 Issue 12 Pages 925-929
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
    A low density composite (Shirasu Balloons Aluminum Composite: SBAC) of volcano glass microballoons (Shirasu Balloons: SB) and aluminum alloy (Al-12%Si) was investigated in terms of the effect of volume fraction (VSB) of SB on tensile strength (σT), compressive strength (σC), shear modulus (G), internal friction coefficient (Q-1) and specific conductivity (C) of SBAC. The value of G decreased exponentially and monotonously with the increase in VSB and showed good agreement with logarithmic mixture rule. The values of σT, σC and C also decreased exponentially with the increase in VSB, but their curves inflected sharply toward low values at about 50vol% of SB. On the other hand, Q-1 value increased linearly with the increase in VSB and the curve inflected sharply toward high value at about 50vol% of SB. The VSB of their knee points (about 50vol%) seemed to be the volume fraction above which contact points of SB in SBAC markedly increased.
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  • Kunio ITO
    1990 Volume 40 Issue 12 Pages 930-935
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
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  • Katsuaki SUGANUMA
    1990 Volume 40 Issue 12 Pages 936-943
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
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  • Toshihiro CHIKADA
    1990 Volume 40 Issue 12 Pages 944-950
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
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  • Hiroshi OIKAWA
    1990 Volume 40 Issue 12 Pages 951
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
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  • Keisuke MATSUURA
    1990 Volume 40 Issue 12 Pages 952-953
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
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  • 1990 Volume 40 Issue 12 Pages 954-956
    Published: December 30, 1990
    Released on J-STAGE: October 30, 2008
    JOURNAL FREE ACCESS
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