Journal of Materials Engineering and Performance

, Volume 21, Issue 8, pp 1785–1792 | Cite as

The Effect of Isothermal Heat Treatment Time on the Microstructure and Properties of 2.11% Al Austempered Ductile Iron

  • H. R. Erfanian-Naziftoosi
  • N. Haghdadi
  • A. R. Kiani-RashidEmail author


In this article, the bainitic transformation during austempering was studied for a 2.11% Al containing ductile iron under different isothermal holding times. The austenitizing time and temperature were selected to be 60 min and 920 °C, respectively, referring to previous studies. The isothermal austempering heat treatments were performed at 350 °C for different durations. Microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural investigations revealed that austempering treatment at 350 °C for durations up to 100 min results in microstructures consisting of carbide-free bainitic ferrite with considerable amounts of retained austenite while the extension of isothermal transformation time leads to precipitation of carbides. Hardness measurements were also carried out the results of which were shown to be consistent with microstructural evolutions.


austempering bainite ductile iron SEM TEM 



The authors wish to thank Mr. B. Bazaz and Mrs. A.T. Yazdi for their worthy assists. We would also like to express our sincere thanks to Professor D.V. Edmonds at the Materials Department of University of Leeds for his valuable support in electron microscopy.


  1. 1.
    I.C.H. Hughes, Ductile Iron, Metals Handbook, Casting, Vol 15, 9th ed., BCIRA International Center for Cast Metals Technology, Great Britain, 1988, p 647–666Google Scholar
  2. 2.
    R. Elliott, Cast Iron Technology, Butterworths & Co. (Publishers) Ltd., London, 1988Google Scholar
  3. 3.
    H.T. Angus, Cast Iron, Butterworths & Co. Publishers Ltd., London, 1978Google Scholar
  4. 4.
    M. Nili-Ahmadabadi, E. Niyama, and J. Echigoya, Transmission Electron Microscopy Study of High Temperature Bainitic Transformation in 1 wt.% Mn Ductile Iron, Mater. Sci. Eng. A Struct. Mater., 1995, 194, p 87–98CrossRefGoogle Scholar
  5. 5.
    M. Cemal Cakir and Y. Isik, Investigating the Machinability of Austempered Ductile Irons Having Different Austempering Temperatures and Times, Mater. Des., 2008, 29, p 937–942CrossRefGoogle Scholar
  6. 6.
    E. Dorazil, B. Barta, E. Munsterova, L. Stransky, and A. Huvar, High-Strength Bainitic Ductile Cast Iron, AFS Int. Cast. Met. J., 1982, 7.2, p 52–62Google Scholar
  7. 7.
    L. Sidjanin, R.E. Smallman, and S.M.A. Boutorabi, Microstructure and Fracture of Aluminum Austempered Ductile Iron Investigated Using Electron Microscopy, Mater. Sci. Technol., 1994, 10, p 711–720Google Scholar
  8. 8.
    A.R. Kiani-Rashid and D.V. Edmonds, Graphite Phase Formation in Al-Alloyed Ductile Irons, Int. J. Eng., 2002, 15(3), p 261–272Google Scholar
  9. 9.
    A.R. Kiani-Rashid, “The Effect of Aluminum on the Structure and Heat Treatment Conditions on Austempered Ductile Iron,” Ph.D. Thesis, School of Materials, University of Leeds, UK, 2000Google Scholar
  10. 10.
    A.R. Kiani-Rashid and D.V. Edmonds, Microstructural Characteristics of Al-Alloyed Austempered Ductile Irons, J. Alloys. Compd., 2009, 477, p 391–398CrossRefGoogle Scholar
  11. 11.
    R.P. Walson, Aluminum Alloyed Cast Iron Properties Used in Design, AFS Trans., 1997, 5, p 51–58Google Scholar
  12. 12.
    A. Shayesteh-Zeraati, H. Naser-Zoshki, A.R. Kiani-Rashid, and M.R. Yousef-Sani, The Effect of Aluminum Content on Morphology, Size, Volume Fraction and Number of Graphite Nodules in Ductile Iron, J. Mater. Des. Appl., 2010, 224, p 117–122Google Scholar
  13. 13.
    H. Bayati and R. Elliott, Relationship Between Structure and Mechanical Properties in High Manganese Alloyed Ductile Iron, Mater. Sci. Technol., 1995, 11, p 284–293Google Scholar
  14. 14.
    M. Bahmani and R. Elliott, Isothermal Transformation Diagrams for Alloyed Ductile Cast Iron, Mater. Sci. Technol., 1994, 10, p 1050–1056CrossRefGoogle Scholar
  15. 15.
    A. Kutsov, Y. Taran, K. Uzlov, A. Krimmel, and M. Evsyukov, Formation of Bainite in Ductile Iron, Mater. Sci. Eng. A Struct. Mater., 1999, 273–275, p 480–484CrossRefGoogle Scholar
  16. 16.
    J.W. Christian and D.V. Edmonds, Phase Transformations in Ferrous Alloys, AIME, Warrendale, PA, 1984, p 293–325Google Scholar
  17. 17.
    H.K.D.H. Bhadeshia and D.V. Edmonds, Bainite in Silicon Steels: New Composition-Property Approach Part 1, Metal Sci., 1983, 17, p 411–419CrossRefGoogle Scholar
  18. 18.
    A.R. Kiani-Rashid, Influence of Austenitising Conditions and Aluminum Content on Microstructure and Properties of Ductile Irons, J. Alloys. Compd., 2009, 470, p 323–327CrossRefGoogle Scholar
  19. 19.
    A.R. Kiani-Rashid, The Bainite Transformation and the Carbide Precipitation of 4.88% Aluminum Austempered Ductile Iron Investigated Using Electron Microscopy, J. Alloys. Compd., 2009, 474, p 490–498CrossRefGoogle Scholar
  20. 20.
    H.K.D.H. Bhadeshia, Bainite in Steels, Transformation, Microstructure and Properties, second ed, IOM Communications Ltd, London, 2001, p 388–397Google Scholar

Copyright information

© ASM International 2011

Authors and Affiliations

  • H. R. Erfanian-Naziftoosi
    • 1
  • N. Haghdadi
    • 1
  • A. R. Kiani-Rashid
    • 1
    Email author
  1. 1.Department of Materials Engineering, Faculty of EngineeringFerdowsi University of MashhadMashhadIran

Personalised recommendations