Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
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Volume 57, Issue 8
Displaying 1-6 of 6 articles from this issue
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RESEARCH REPORT
  • Dieless drawing process of extruded non-circular aluminum alloy tubes with double hollow section
    Tsuyoshi FURUSHIMA, Ken-ichi MANABE
    2007 Volume 57 Issue 8 Pages 351-356
    Published: 2007
    Released on J-STAGE: September 30, 2007
    DOIhttps://doi.org/10.2464/jilm.57.351
    JOURNAL FREE ACCESS
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    Dieless drawing technique can thin down tubes by combining locally heating and tensile deformation of tubes without dies and tools. In this study, the dieless drawing process is applied to non-circular 1100 and 3003 aluminum alloy extruded tubes with double hollow section for heat exchangers. Fundamental deformation behavior of the tubes in the dieless drawing is investigated experimentally. Multi-pass dieless drawing is performed for the tubes to obtain larger reduction in area. The limiting reduction in area of A3003 tubes is 40% larger than 35% of A1100 in a singles pass drawing. Reduction in area 57.75% is obtained by two-pass dieless drawing for A3003 tubes. Geometrical similarity law in cross section is satisfied for the aluminum extruded tubes with double-hollow-section. In addition, surface characteristic and microstructure of the tubes after the dieless drawing is observed to investigate the effect of microscopic factors on the deformation behavior and the drawability in the dieless drawing. The results show that the surface roughness of the tubes increases with increasing reduction in area. Furthermore, the rate of increasing surface roughness depends on the grain size of initial tubes. It is found that the microstructure and the surface characteristic affect the deformation behavior and the drawability in the dieless drawing.
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  • Evaluation of tensile strength and fatigue strength of commercial pure aluminum/tough pitch copper friction-welded joints by deformation heat input
    Hiizu OCHI, Yoshiaki YAMAMOTO, Takashi YAMAZAKI, Takeshi SAWAI, Gosaku ...
    2007 Volume 57 Issue 8 Pages 357-361
    Published: 2007
    Released on J-STAGE: September 30, 2007
    DOIhttps://doi.org/10.2464/jilm.57.357
    JOURNAL FREE ACCESS
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    The relationships between the deformation heat input at the upset stage and joint strength, and between upset burn-off length and joint strength were examined on 1050 pure aluminum to C1100 tough pitch copper friction-welded joints. Joint quality was evaluated from tensile strength and fatigue strength. It was found that the deformation heat input at the upset stage or the upset burn-off length could be correlated well with joint strength, and when the deformation heat input at the upset stage or upset burn-off length exceeded a certain value, a stable tensile strength was obtained. The mixing layer consists of intermetallic compounds and A1050 was formed at the weld interface, and joints having thick mixing layer fractured at the weld interface. Joint efficiencies of sound joints for the fatigue limit of the A1050 base metal was 88–100%. Judging from the fatigue limit, the sound joints could be produced when either the deformation heat input at the upset stage or the upset burn-off length exceeded a certain value.
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  • Influence on plastic deformed with restoration behavior of soft aluminum sheet
    Nobuo HATANAKA, Takashi IIZUKA, Norio TAKAKURA
    2007 Volume 57 Issue 8 Pages 362-365
    Published: 2007
    Released on J-STAGE: September 30, 2007
    DOIhttps://doi.org/10.2464/jilm.57.362
    JOURNAL FREE ACCESS
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    Restoration tests were carried out using specimens bulged to different heights and diameters. The diameters use an Erichsen test device and a specially fabricated bulging die. Soft aluminum (Al–O) sheets were used as test specimens. The bulged sheets were compressed in the upper and lower plates of the material testing machine. The thickness of the specimens was changed from 0.4 to 2 mm. And the effect of thickness on the restoration behavior of the bulged specimens was investigated. The results of the experiments showed that some circular wrinkle patterns appeared on the sheet surface due to buckling at the bulged portion during compression when the bulged specimen was compressed to a flat sheet. Some restoration patterns were observed depending on the thickness of the material. The number of wrinkles formed after restoration was influenced by the thickness of the material, the height of the bulge and its diameter.
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  • Capacitance characteristics and structure of anodic oxide films grown on rapidly quenched aluminum alloys
    Takashi MOCHIZUKI, Hiroshi MORIYAMA, Keiichi TERASHIMA
    2007 Volume 57 Issue 8 Pages 366-370
    Published: 2007
    Released on J-STAGE: September 30, 2007
    DOIhttps://doi.org/10.2464/jilm.57.366
    JOURNAL FREE ACCESS
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    Anodic oxide films grown on rapidly quenched aluminum alloys containing 2 at% Ti, Zr, Ta, Nb or Hf were characterized. The capacitance of the film on each alloy was found to be related to the dielectric constant of the alloying metal oxide film. In addition, the capacitance was found to depend on the degree of the exposure of the alloyed metal to the electrolyte, due to aluminum dissolution during the anodic oxidation. Capacitance varied with time, temperature and pH of the electrolyte in the anodic oxidation process. An oxide film of the barrier type was observed on Al3Zr by TEM, whereas the oxidation film of the Al–Ti alloy had a dual structure consisting of an inner layer with lower TiO2 content and an outer one with higher TiO2 content. It is considered that these phenomena were caused by the preferential dissociation of aluminum in the anodic oxidation process.
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