Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
Volume 28, Issue 10
Displaying 1-8 of 8 articles from this issue
  • Shotaro MOROZUMI
    1978 Volume 28 Issue 10 Pages 481-482
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
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  • Koichi MURAKAMI, Eiichi SATO
    1978 Volume 28 Issue 10 Pages 483-486
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    Frequency response of films formed at various potentials and corrosion potential of magnesium electrodes in various concentrations of Na3PO4 solution was investigated. An electronic potentiostat with a signal generator was used to control both D. C. and superposed A. C. potentials of the electrode. The impedance at the frequency from 10 to 2 × 104Hz was determined by measuring the amplitude and the phase shift of A. C. and A. C. voltage. The capacitance of the film on the electrode in 0.25M Na3PO4 increases with time, probably indicating dissolution or deterioration of the film. The capacitance of the films on the electrode in the Na3PO4 solution decreases with increase in the concentration. The fact shows that the film is easily formed. The dissolution and formation of the film on magnesium simultaneously occurs in 0.25M Na3PO4 at -1.40V to -1.20V. The deterioration of the film occurs in the potential region over +1.60V (vs. Hg/HgO•0.5N NaOH).
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  • Hajime YAMADA, Takio TANAKA
    1978 Volume 28 Issue 10 Pages 487-492
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    Effect of the addition of Ni to Al-Zr alloys has been studied in order to improve the heatresisting strength of the alloys depending on the restriction of recrystallization. The addition of a small amount of Ni about 0.1% or less has a little effect on the recrystallization temperature or electrical conductivity, but is effective to increase heatresisting strength of the Al-Zr alloys. Low temperature temper hardening recognized in the Al-Zr alloys is also considerably increased by the addition of a small amount of Ni regardless of the precipitation heat treatment.
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  • Yoshio KATO, Mototaro SATO, Masataka FUKUI
    1978 Volume 28 Issue 10 Pages 493-498
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    The r-values in tensile deformation of polycrystalline aggregates taken in seven directions to the rolling direction of textured sheets 90% cold rolled were determined. The r-values were also theoretically calculated using the maximum resolved shear stress for the slip on the {111} <110> system. Both r-values experimental and calculated are in good agreement on single crystals. Both of the polycrystals which have simultaneously two prefered crystallographic orientation (112) <111> and (110) [112] are slightly different. The r-values of polycrystalline sheets changes at various cutting angles, for instance, the maximum value is achieved at 45 deg. The slip system applied for theoreti-cal calculation is found to be satisfactory by observing traces of the slip band.
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  • Tadashi MOMONO, Katsuya IKAWA
    1978 Volume 28 Issue 10 Pages 499-505
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    Various compositions of ammonium-chloride solutions were cast to study the influences of superheat and fluid flow on the formation of the equiaxed crystal zone. Various parts of residual liquid in solidifing Al-4.5%Cu alloys were quenched in water for the same purpose. The fluid motion gives rise to fluctuation of temperature at the solidification front, lowers the temperature of bulk liquid, and reduces the temperature gradient. These effects promote dendrite fragmentation, and the fragments survive. The relationship between the experimental facts and the explanation currently proposed on the origin of equiaxed zone is also discussed.
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  • Tatsuo SATO, Yo KOJIMA, Tsuneo TAKAHASHI
    1978 Volume 28 Issue 10 Pages 506-513
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    Behaviors of G. P. zone formation and growth in Al-Cu and Al-Zn alloys were investigated by means of electric resistivity measurements and X-ray small angle scattering method. Resistivities of both alloys unchange in a certain period of aging time in which the X-ray integrated intensity is saturated (flat region). The limit-temperature for G. P. zone formation determined by the resistivity at the flat region is peculiar to the concentration of the alloys and independent of the quenching temperature. These results imply the existence of a metastable miscibility gap in both alloys. The resistivity at the flat region is considerably influenced by the quenching temperature, because the G. P. zone's distribution (zone size and its density) at the flat region changes with the quenching temperature although the volume fraction of zones is the same.
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  • Cong Danh NGUYEN, Takeshi MURAKAMI, Tsuneo TAKAHASHI
    1978 Volume 28 Issue 10 Pages 514-520
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
    Development of cube texture during final annealing in Al-1.1%Mn alloy containing manganese as in solid solution and as a precipitate phase after partial recrystallization and moderate deformation was investigated by optical and electron microscopy, and X-ray diffraction. The frequency of formation of cube grain at partial recrystallization stage plays an important role because of the preferential growth of cube grain by strain induced boundary migration. In this case, sharp cube texture shows a spread of orientation around <100> axis parallel to the rolling direction. Precipitation of Al6Mn prior to final annealing results in formation of retained rolling texture and the development of cube texture is suppressed.
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  • Yoshiyuki KOBAYASHI
    1978 Volume 28 Issue 10 Pages 521-527
    Published: October 30, 1978
    Released on J-STAGE: July 23, 2008
    JOURNAL FREE ACCESS
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