Time-resolved and In-situ Observation of Graphite Nucleation Position and Shape Evolution in Hypereutectic Ductile Cast Iron with Mg Addition

• Chatcharit Kiattisaksri

  Dept Materials Science and Engineering, Kyoto University

• Sugiyama Akira

  Dept Mechanical Engineering for Transportation, Osaka Sangyo University

• Morishita Kohei

  Dept Materials Science and Engineering, Kyoto University (Present address : Department of Materials Science and Engineering, Kyushu University)

• Yasuda Hideyuki

  Dept Materials Science and Engineering, Kyoto University

Bibliographic Information

Other Title

• Mg添加過共晶球状黒鉛鋳鉄におけるグラファイトの核生成と形状変化の時間分解その場観察
• Mg テンカ カキョウショウ キュウジョウ コクエン チュウテツ ニ オケル グラファイト ノ カク セイセイ ト ケイジョウ ヘンカ ノ ジカン ブンカイ ソノ バ カンサツ

Abstract

  Nucleation position, floating and morphological change of graphite nodules during solidification of hypereutectic ductile cast iron with Mg addition was observed in-situ using synchrotron radiation X-ray imaging. Graphite nucleated on pre-existing inclusions (i. e. MgS and Mg-containing oxysulfide) in the melt around austenite dendrites and most of the graphite nodules floated due to the buoyancy force. The floating graphite nodules were engulfed or entrapped austenite dendrites within several seconds. Floating distance of graphite nodules was shorter than dendrite arm spacing. The nucleation events near the dendrites and solute exchange between austenite dendrites and graphite nodules resulted in the short floating distance. The engulfment / entrapment of graphite nodules into austenite dendrites promoted the secondary nucleation of graphite in the melt and consequently influenced size and number of graphite nodules. In addition, two different phenomena also contributed to the morphological transition from spheroidal shape. One is the coalescence of graphite nodules and the other is the growth of graphite nodules in the austenite.

Journal

• Journal of Japan Foundry Engineering Society

  Journal of Japan Foundry Engineering Society 90 (10), 602-612, 2018-10-25

  Japan Foundry Engineering Society

Keywords

• Ductile cast iron
• X-ray imaging
• Time-resolved and in-situ observation
• Divorced eutectic

Details

• CRID: 1390001288085902080
• NII Article ID: 130007502845
• NII Book ID: AN10514770
• DOI: 10.11279/jfes.90.602
• ISSN: 21855374
• ISSN: 13420429
• NDL BIB ID: 029309593
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I029309593
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed