Time Evolution of Solidification Structure in Ductile Cast Iron with Hypereutectic Compositions

Kiattisaksri Chatcharit, Akira Sugiyama, Kohei Morishita, Taka Narumi, Kentaro Kajiwara, Hideyuki Yasuda

    研究成果: ジャーナルへの寄稿学術誌査読

    3 被引用数 (Scopus)


    The microstructure evolution in ductile cast iron with magnesium addition was observed in situ by using X-ray radiography (two-dimensional observation) and time-resolved tomography (three-dimensional observation) in the BL20XU of a synchrotron radiation facility, SPring-8 (Hyogo, Japan). In the two-dimensional observation, graphite nodules nucleated in the melt and floated up immediately after nucleation. The floating was terminated by engulfment of graphite nodules into austenite dendrites. The radiography indicated that the average floating distance was shorter than the dendrite arm spacings in the 100-μm-thick specimen. Because the short distance could be influenced by the sample confinement, time-resolved tomography was performed by using a pink X-ray beam in the BL28B2 of SPring-8. Graphite nodules that nucleated in the melt (probably on magnesium–oxygen–sulfur inclusions in the melt) floated and were engulfed by austenite dendrites within several seconds, even in the bulk specimen. Although the average distance in the bulk specimen was approximately twice as large as that in the 100-μm-thick specimen, floating after nucleation and engulfment into austenite dendrites within a short duration were observed commonly from both techniques. The sequence of nucleation and engulfment had a critical effect on the number and size of the graphite nodules.

    ジャーナルInternational Journal of Metalcasting
    出版ステータス出版済み - 7月 1 2020

    !!!All Science Journal Classification (ASJC) codes

    • 材料力学
    • 産業および生産工学
    • 金属および合金
    • 材料化学


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