Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
Volume 71, Issue 10
Displaying 1-5 of 5 articles from this issue
RESEARCH ARTICLE
  • Mitsuru Adachi, Daisuke Terada, Shotaro Yusa, Shuji Koiwai, Yoshiki Ha ...
    2021 Volume 71 Issue 10 Pages 441-449
    Published: October 15, 2021
    Released on J-STAGE: November 15, 2021
    JOURNAL FREE ACCESS

    The mechanical properties of Al-10%Si-Mg system alloys containing Mn up to 1.5% fabricated by selective laser melting (SLM) with preheat temperature of 160°Cor 200°Cfor 15hours were studied by means of tensile test, hardness measurement and DSC analysis. The strength of the Mn added alloys was about 100 to 150MPa higher than that of the Mn free alloy. The bottom of the 1.5%Mn added alloy showed about 500MPa and 400MPa under preheat condition of 160°C and 200°C, respectively. Many compounds containing Si with size of about 40nm were observed at the bottom of the 1.5%Mn added alloy with preheat temperature of 200°C by STEM-BF image. Mn enriched zone was observed at eutectic (α-Al, Si) area of the 1.5%Mn added alloy by STEM-EDS. It is possible that Mn enriched zone directly or indirectly causes the high strength.

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  • Ryohei Shinno, Makoto Hino, Ryoichi Kuwano, Koji Monden, Masaaki Sato, ...
    2021 Volume 71 Issue 10 Pages 450-454
    Published: October 15, 2021
    Released on J-STAGE: November 15, 2021
    JOURNAL FREE ACCESS

    In this study, A2017-T4 aluminum alloy was plated with electroless Ni-P with different phosphorus content and rotary bending fatigue test was conducted to investigate the effect of hydrogen by plating on fatigue properties. The fatigue strength of the low-phosphorus type Ni-P plated specimen was higher than that of the untreated specimen, while that of the high-phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. The decrease in fatigue strength of the high phosphorus type plating specimen was attributed to hydrogen induced by plating from hydrogen analysis. Thus, despite the previous report that 2000 series aluminum alloys do not exhibit hydrogen embrittlement in slow strain rate tensile tests under wet condition, it was found that A2017-T4 aluminum alloy undergo hydrogen embrittlement when the alloy is plated with high-phosphorus type electroless Ni-P and fatigue-tested on rotary bending machine.

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