Skip to main content
Log in

Why is Graphite Spherical in Ductile Iron? A Study of Elemental Distributions at Interfaces in Ductile Iron Using Atom Probe Tomography and Transmission Electron Microscopy

  • Published:
International Journal of Metalcasting Aims and scope Submit manuscript

Abstract

Atom probe tomography (APT) with high sensitivity and spatial resolution was applied to study the elemental distributions in spheroidal graphite in ductile iron. A specimen of quenched ductile iron with some graphite nodules in direct contact with liquid phase was used in this study to understand the role of alloying elements in spheroidal graphite formation. Compositional analysis was performed at the graphite/matrix interface and graphite/nuclei interface using APT and EDX (energy-dispersive X-ray). Distributions of various alloying elements at interfaces were obtained. Compositional gradients were observed at both the graphite/liquid interface and the graphite/nuclei interface. The spheroidal graphite nuclei were differentiated as the complex compound made of oxide, nitride and sulfide. The graphite–nuclei interface was shown to be semi-coherent/incoherent using the transmission electron microscopy, with a high density of crystallographic defects and high curvatures in the graphite basal planes growing off the nuclei. Intercalation of large nodulizing elements within and in between the graphite basal planes may account for the spherical morphology of the graphite in ductile irons.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10

Similar content being viewed by others

References

  1. ASM Handbooks, Casting, Cast Iron, vol. 15 (ASM International, 2008)

  2. W.C. Johnson, H.B. Smartt, The role of interphase boundary adsorption in the formation of spheroidal graphite in cast iron. Metall. Trans. A 8A, 553–564 (1977)

    Article  CAS  Google Scholar 

  3. S.E. Franklin, R.A. Stark, Application of secondary ion mass spectrometry to study of graphite morphology in cast iron. Metal Sci. 18, 187–200 (1984)

    Article  CAS  Google Scholar 

  4. S.E. Franklin, R. A. Stark, Further Use of Secondary Ion Mass Spectrometry in the Study of Graphite Morphology Control in Cast Irons, in The Physical Metallurgy of Cast Iron, North-Holland (1984) pp. 25–35

  5. J.J. Adjizian, C.D. Latham, S. Öbergc, P.R. Briddond, M.I. Heggie, DFT study of the chemistry of sulfur in graphite, including interactions with defects, edges and folds. Carbon 62, 256–262 (2013)

    Article  CAS  Google Scholar 

  6. I. Minkoff, The Physical Metallurgy of Cast Iron (Wiley, Hoboken, 1983)

    Google Scholar 

  7. T. Skaland, Ø. Grong, T. Grong, Metall. Trans. A 24A, 2321–2345 (1993)

    Article  CAS  Google Scholar 

  8. J.K. Solberg, M.I. Onsøien, Nuclei for heterogeneous formation of graphite spheroids in ductile cast iron. Mater. Sci. Technol. 17, 1238–1242 (2001)

    Article  CAS  Google Scholar 

  9. B. Miao, D.O. North Wood, W. Bian, K. Fang, M.H. Fan, Structure and growth of platelets in graphite spherulites in cast iron. J. Mater. Sci. 29, 255–261 (1994)

    Article  CAS  Google Scholar 

  10. B. Miao, K. Fang, W. Bian, On the microstructure of graphite spherulites in cast irons by TEM and HREM. Acta Metal. Mater. 38, 2167–2174 (1990)

    Article  CAS  Google Scholar 

  11. I.E. Bolotov, V.I. Syreishchikova, S.G. Guterman, Phys. Met. Metallogr. 4, 144–146 (1957)

    Google Scholar 

  12. A.P. Lyubchenko, M.V. Mozharov, Y.G. Bobro, Phys. Met. Metallogr. 12, 63–68 (1961)

    Google Scholar 

  13. M. Hillert, Y. Lindblom, J. Iron Steel Inst. 176, 388 (1954)

    CAS  Google Scholar 

  14. J. Qing, V.L. Richards, D.C. Van Aken, Examination of nodular graphite formation and austenite solidification in ductile iron. Trans. Am. Foundry Soc. 123, 271–281 (2015)

    Google Scholar 

  15. J. Qing, V.L. Richards, D.C. Van Aken, M. Xu, Staged growth of spheroidal graphite in ductile irons. Trans. Am. Foundry Soc. 125, 161–171 (2017)

    CAS  Google Scholar 

  16. J. Qing, V.L. Richards, D.C. Van Aken, Examination of nodular graphite formation and austenite solidification in ductile iron. Metall. Mater. Trans. A Col. 47A, 6197–6213 (2016)

    Article  Google Scholar 

  17. https://en.wikipedia.org/wiki/Isotopes_of_magnesium

  18. D.M. Stefanescu, D.K. Brandyopadhyay, On the solidification kinetics of spheroidal graphite cast iron, in Physical Metallurgy of Cast Iron IV: Proceedings of the Fourth Intl Symposium Held in Tokyo, Japan, Materials Research Society (1990), pp. 15–26

  19. H. Fredriksson, J. Stjerndahl, J. Tinoco, On the solidification of nodular cast iron and its relation to the expansion and contraction. Mater. Sci. Eng. A 413–414, 363–372 (2005)

    Article  Google Scholar 

  20. E. Scheil, L. Hutter, Untersuchungen über die Kristallisation des Gusseisens mit Kugelgraphit (Archiv fur das Eisenhuttenwesen, Mai/Juni, 1953), pp. 237–246

    Google Scholar 

  21. H. Hecht, J.C. Margerie, Mem. Sci. Rev. Metallurg. 68, 325–338 (1971)

    Google Scholar 

  22. B. Lux, F. Mollard, I. Minkoff, On the formation of envelopes around graphite in cast iron, in The Metallurgy of Cast Iron: Proceedings of the Second International Symposium on the Metallurgy of Cast Iron, Geneva, Switzerland, Georgi Publishing (1974), pp. 371–400

  23. M. Celis, B. Domengès, E. Hug, J. Lacaze, Analysis of nuclei in a heavy-section nodular iron casting. Mater. Sci. Forum 925, 173–180 (2018). ISSN 1662-9752

Download references

Acknowledgements

This study is funded by Ductile Iron Society. The authors would like to express their gratitude to the Ductile Iron Society Research Committee for their valuable inputs to this research Project. Dr. Dieter Isheim from Northwestern University is acknowledged for preparing the atom probe sample and performing the atom probe tomography experiment. The authors would like to thank Dr. Van Aken and Dr. Von Richards from Missouri University of Science & Technology for providing valuable technical discussions. The authors also appreciate that Materials Research Center at Missouri University of Science & Technology provided characterization instruments for this study.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jingjing Qing.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This paper is an invited submission to IJMC selected from presentations at the 6th Keith Millis on Ductile Iron held October 23–26, 2018, at the Sonesta Resort, Hilton Head Island, SC. It is published in the IJMC by permission of the DIS (Ductile Iron Society).

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Qing, J., Xu, M. & Pikhovich, V. Why is Graphite Spherical in Ductile Iron? A Study of Elemental Distributions at Interfaces in Ductile Iron Using Atom Probe Tomography and Transmission Electron Microscopy. Inter Metalcast 14, 1115–1122 (2020). https://doi.org/10.1007/s40962-020-00443-0

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40962-020-00443-0

Keywords

Navigation