Journal of Japan Institute of Light Metals
Online ISSN : 1880-8018
Print ISSN : 0451-5994
ISSN-L : 0451-5994
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Volume 63, Issue 8
Displaying 1-3 of 3 articles from this issue
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RESEARCH ARTICLE
  • Relationship between resolution and rotation stage in imaging X-ray CT
    Masakazu Kobayashi, Yoshihiko Sugihara, Hiroyuki Toda, Kentaro Uesugi
    Article type: RESEARCH ARTICLE
    2013 Volume 63 Issue 8 Pages 273-278
    Published: August 30, 2013
    Released on J-STAGE: September 30, 2013
    DOIhttps://doi.org/10.2464/jilm.63.273
    JOURNAL FREE ACCESS
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    In this study, evaluation of precision in rotation stage and investigation of effect of rotation stage blurring on resolution are performed in imaging X-ray tomography set-up, which allows nano-scale observation, for the purpose of improving resolution in X-ray tomography. In the result of precision evaluation of rotation stage in high-resolution imaging X-ray tomography, fluctuation, which was approximately 35 nm in maximum and approximately 13 nm in average, was found. This fluctuation was under 1 pixel. In the simulation that analyzed effect of fluctuation in rotation stage, it was found that long periodic fluctuation deteriorate reconstructed image terribly. But, impulse-like fluctuation does not almost affect reconstructed image quality. However, reconstructed image is deteriorated when the frequency of impulse-like fluctuation increase. If long periodic fluctuation, which was observed in the precision evaluation, is corrected, the resolution improvement was confirmed though the fluctuation was less than 1 pixel.
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  • Structure and mechanical properties of Mg–Ca and Mg–Ca–Zr alloys
    Yosuke Tamura, Yoshikazu Sugimoto, Hiroshi Soda, Alexander Mclean
    Article type: RESEARCH ARTICLE
    2013 Volume 63 Issue 8 Pages 279-285
    Published: August 30, 2013
    Released on J-STAGE: September 30, 2013
    DOIhttps://doi.org/10.2464/jilm.63.279
    JOURNAL FREE ACCESS
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    Cast Mg–Ca and Mg–Ca–Zr alloys were prepared from elemental metals, Mg–5Ca, and Mg–33Zr master alloys. The microstructure was examined and tensile tests performed. The microstructures of the cast Mg–Ca alloys consist of primary α-Mg dendrites and a degenerated lamellar eutectic. An addition of zirconium transformed coarse primary α-Mg dendrites to fine globular grains of approximately 20∼35 μm in diameter. Hardness increased for both Mg–Ca and Mg–Ca–Zr alloys with calcium contents, and there was a slope change in hardness increase at about 0.3%Ca, at which eutectic containing Mg2Ca started to appear at grain boundaries. The value of 0.2% proof stress also increased for both alloys, showing higher values due to a grain refining effect. The values of tensile strength for Mg–Ca–Zr alloys were also higher than those of the Mg–Ca alloys, while the strength did not improve beyond 0.3%Ca. Fracture occurred owing to the decohesion within eutectic regions and the cracks propagated though the regions. Thus, an increase in the eutectic regions leads to a reduction in ductility. In particular, the Mg–Ca–Zr alloys, with calcium content as little as 0.3%, showed a significant reduction in ductility, negating the effect of grain refinement.
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