Formation of Austenite in Additively Manufactured and Post-Processed Duplex Stainless Steel Alloys

  • A. D. Iams
  • J. S. Keist
  • T. A. PalmerEmail author


The additive manufacturing of duplex stainless steels has been limited by the inability to maintain a balanced ferrite/austenite microstructure. In order to investigate the impact of the complex thermal histories inherent to the additive manufacturing process on austenite fractions and morphology, a laser-based directed energy deposition process was used to fabricate lean (UNS S32101), standard (UNS S32205), and super (UNS S32507) duplex structures. In these structures, the austenite phase fractions ranged from 16.1 ± 1.1 pct in the lean, to 38.5 ± 1.6 pct in the standard, and 58.3 ± 0.1 pct in the super duplex stainless steel grades. While the overall austenite levels were comparable to those found in wrought alloys, the austenite fractions increased with build height as preheating from previously deposited material promoted the ferrite to austenite transformation. Of the austenite morphologies observed in each of the duplex stainless steel grades, intragranular austenite was dominant, comprising between 55 and 76 pct of the austenite present within each build. The intragranular austenite formed during reheating and its formation was enhanced by the presence of submicron inclusions which originated from the powder feedstock and served as heterogenous nucleation sites. After post-process hot isostatic pressing heat treatment, the austenite morphology became more similar in appearance to that observed in the wrought condition. The overall austenite fractions in the post-processed lean (28.2 ± 0.7 pct), standard (57.6 ± 0.2 pct), and super (66.5 ± 0.3 pct) duplex grades increased over their respective as-deposited conditions and became more uniform with changes in build height.



The authors acknowledge the Office of Naval Research Manufacturing Technology program and the Applied Research Laboratory’s Institute for Manufacturing and Sustainment Technologies which is funded under the Naval Sea Systems Command (NAVSEA) contract #N00024-12-D-6404. A.D.I. acknowledges the support from the American Welding Society Foundation Research Fellowship. The authors wish to thank the Center for Innovative Materials Processing through Direct Digital Deposition (CIMP-3D) for the use of their equipment, laboratory facilities, Mr. Jay Tressler for fabrication of the builds, and Ms. Marissa Brennan for completing the X-ray CT scans and the porosity analysis. We also acknowledge Mr. Magnus Ahlfors and Mr. Jim Shipley at Quintus Technologies for performing the hot isostatic pressing and providing helpful discussions.


  1. 1.
    A. Vinoth-Jebaraj, L. Ajaykumar, C.R. Deepak, and K. V. V. Aditya: J. Adv. Res., 2017, vol. 8, pp. 183–99.CrossRefGoogle Scholar
  2. 2.
    Westinghouse Electric Company: Engineered Safety Features, AP1000 Design Control Document Revision 18, vol. 6, 2010.Google Scholar
  3. 3.
    I. Alvarez-Armas and S. Degallaix-Moreuil, eds.: Duplex Stainless Steels, John Wiley & Sons, New Jersey, 2013.Google Scholar
  4. 4.
    R.N. Gunn: Duplex Stainless Steels: Microstructure, Properties and Applications, Woodhead Publishing, 1997.CrossRefGoogle Scholar
  5. 5.
    G. Mohammed, M. Ishak, S. Aqida, and H. Abdulhadi: Metals (Basel)., 2017, vol. 7, p. 39.CrossRefGoogle Scholar
  6. 6.
    A.J. Ramirez, J.C. Lippold, and S.D. Brandi: Metall. Mater. Trans. A, 2003, vol. 34, pp. 1575–97.CrossRefGoogle Scholar
  7. 7.
    C.M. Garzón and A.J. Ramirez: Acta Mater., 2006, 54(12), pp. 3321–3331.CrossRefGoogle Scholar
  8. 8.
    J.W. Elmer, T.A. Palmer, and E.D. Specht: Metall. Mater. Trans. A, 2007, vol. 38, pp. 464–75.CrossRefGoogle Scholar
  9. 9.
    N. Llorca-Isern, H. López-Luque, I. López-Jiménez, and M.V. Biezma: Mater. Charact., 2016, 112, pp. 20–9.CrossRefGoogle Scholar
  10. 10.
    T.H. Chen, K.L. Weng, and J.R. Yang: Mater. Sci. Eng. A, 2002, vol. 338, pp. 259–70.CrossRefGoogle Scholar
  11. 11.
    A. Igual-Muñoz, J. García-Antón, J.L. Guiñón, and V. Pérez-Herranz: Corrosion, 2005, vol. 61, pp. 693–705.CrossRefGoogle Scholar
  12. 12.
    J.Y. Maetz, T. Douillard, S. Cazottes, C. Verdu, and X. Kléber: Micron, 2016, 84, pp. 43–53.CrossRefGoogle Scholar
  13. 13.
    K.M. Lee, H. Cho, and D.C. Choi: J. Alloys Compd. 1999, 285, 156–161.CrossRefGoogle Scholar
  14. 14.
    R.B. Bhatt, H.S. Kamat, S.K. Ghosal, and P.K. De: JMEPEG, 1999, vol. 8, pp. 591–7.CrossRefGoogle Scholar
  15. 15.
    V. Muthupandi, P. Bala-Srinivasan, S.K. Seshadri, and S. Sundaresan: Mater. Sci. Eng. A, 2003, vol. 358, pp. 9–16.CrossRefGoogle Scholar
  16. 16.
    V. Muthupandi, P. Bala-Srinivasan, V. Shankar, S.K. Seshadri, and S. Sundaresan: Mater. Lett., 2005, 59 (18), pp. 2305–2309.CrossRefGoogle Scholar
  17. 17.
    H. Sieurin and R. Sandstrom: Mater. Sci. Eng. A, 2006, vol. 418, pp. 250–6.CrossRefGoogle Scholar
  18. 18.
    J.M. Gomez de Salazar, A. Soria, and M.I. Barrena: J. Mater. Sci., 2007, vol. 42, pp. 4892–8.CrossRefGoogle Scholar
  19. 19.
    E.M. Westin: Weld. World, 2010, vol. 54, pp. 308–21.CrossRefGoogle Scholar
  20. 20.
    A. Eghlimi, M. Shamanian, and K. Raeissi: Surf. Coat. Technol., 2014, 244, pp. 45–51.CrossRefGoogle Scholar
  21. 21.
    L. Karlsson and J. Börjesson: Sci. Technol. Weld. Join., 2014, vol. 19, pp. 318–23.CrossRefGoogle Scholar
  22. 22.
    Z. Zhang, H. Jing, L. Xu, Y. Han, L. Zhao, and C. Zhou: Appl. Surf. Sci., 2017, vol. 404, pp. 110–28.CrossRefGoogle Scholar
  23. 23.
    Y. Yang, Z. Wang, H. Tan, J. Hong, Y. Jiang, L. Jiang, and J. Li: Corros. Sci., 2012, vol. 65, pp. 472–80.CrossRefGoogle Scholar
  24. 24.
    Z. Zhang, Z. Wang, Y. Jiang, H. Tan, D. Han, and Y. Guo: Corros. Sci., 2012, vol. 62, pp. 42–50.CrossRefGoogle Scholar
  25. 25.
    T. DebRoy, H.L. Wei, J.S. Zuback, T. Mukherjee, J.W. Elmer, J.O. Milewski, A.M. Beese, A. Wilson-Heid, A. De, and W. Zhang: Prog. Mater. Sci., 2018, vol. 92, pp. 112–224.CrossRefGoogle Scholar
  26. 26.
    K.D. Ramkumar, D. Mishra, B.G. Raj, M.K. Vignesh, G. Thiruvengatam, S.P. Sudharshan, N. Arivazhagan, N. Sivashanmugam, and A. Maximus: Mater. Des., 2015, vol. 66, pp. 356–65.CrossRefGoogle Scholar
  27. 27.
    V.A. Hosseini, S. Wessman, K. Hurtig, and L. Karlsson: Mater. Des., 2016, vol. 98, pp. 88–97.CrossRefGoogle Scholar
  28. 28.
    J. Pekkarinen and V. Kujanpää: Phys. Procedia, 2010, vol. 5, pp. 517–23.CrossRefGoogle Scholar
  29. 29.
    A. Mourad, A. Khourshid, and T. Sharef: Mater. Sci. Eng. A, 2012, vol. 549, pp. 105–13.CrossRefGoogle Scholar
  30. 30.
    Z. Zhang, H. Jing, L. Xu, Y. Han, L. Zhao, X. Lv, and J. Zhang: Appl. Surf. Sci., 2018, vol. 435, pp. 352–66.CrossRefGoogle Scholar
  31. 31.
    J.W. Elmer, S.M. Allen, and T.W. Eagar: Metall. Trans. A, 1989, vol. 20, pp. 2117–31.CrossRefGoogle Scholar
  32. 32.
    V.A. Hosseini, K. Hurtig, and L. Karlsson: Mater. Corros., 2017, vol. 68, pp. 405–15.CrossRefGoogle Scholar
  33. 33.
    K.P. Davidson and S. Singamneni: Mater. Manuf. Process., 2016, vol. 31, pp. 1543–55.CrossRefGoogle Scholar
  34. 34.
    K.P. Davidson and S. Singamneni: Jom, 2017, vol. 69, pp. 569–74.CrossRefGoogle Scholar
  35. 35.
    K. Saeidi, L. Kevetkova, F. Lofaj, and Z. Shen: Mater. Sci. Eng. A, 2016, vol. 665, pp. 59–65.CrossRefGoogle Scholar
  36. 36.
    F. Hengsbach, P. Koppa, K. Duschik, M.J. Holzweissig, M. Burns, J. Nellesen, W. Tillmann, T. Tröster, K.-P. Hoyer, and M. Schaper: Mater. Des., 2017, 133, pp. 136–142.CrossRefGoogle Scholar
  37. 37.
    M. Eriksson, M. Lervåg, C. Sørensen, A. Robertstad, B.M. Brønstad, B. Nyhus, R. Aune, X. Ren, and O.M. Akselsen: MATEC Web of Conferences, 2018, vol. 188, pp. 1–8.CrossRefGoogle Scholar
  38. 38.
    G. Posch, K. Chladil, and H. Chladil: Weld. World, 2017, vol. 61, pp. 873–82.CrossRefGoogle Scholar
  39. 39.
    ASTM E1019: Standard Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Fusion Techniques, ASTM International, West Conshohocken, PA, 2018.Google Scholar
  40. 40.
    ASTM E1097: Standard Guide for Determination of Various Elements by Direct Current Plasma Atomic Emission Spectrometry, ASTM International, West Conshohocken, PA, 2012.Google Scholar
  41. 41.
    ASTM 276: Standard Specification for Stainless Steel Bars and Shapes, West Conshohocken, PA, 2017.Google Scholar
  42. 42.
    L. Kaufman and H. Bernstein: Computer Calculation of Phase Diagrams, Academic Press, New York, 1970.Google Scholar
  43. 43.
    N. Saunders and A. Peter-Miodownik: CALPHAD (Calculation of Phase Diagrams): A Comprehensive Guide, Elsevier, New York, 1998.Google Scholar
  44. 44.
    H. Lukas, S.G. Fries, and B. Sundman: Computational Thermodynamics: The CALPHAD Method, Cambridge University Press, Cambridge, 2007.CrossRefGoogle Scholar
  45. 45.
    Z.K. Liu: J. Phase Equilibria Diffus., 2009, vol. 30, pp. 517–34.CrossRefGoogle Scholar
  46. 46.
    ASTM B213: Standard Test Methods for Flow Rate of Metal Powders Using the Hall Flowmeter Funnel, ASTM International, West Conshohocken, PA, 2013.Google Scholar
  47. 47.
    ASTM B212: Standard Test Method for Apparent Density of Free-Flowing Metal Powders Using the Hall Flowmeter Funnel, ASTM International, West Conshohocken, PA, 2013.Google Scholar
  48. 48.
    ASTM B527: Standard Test Method for Determination of Tap Density of Metal Powders and Compounds, ASTM International, West Conshohocken, PA, 2015.Google Scholar
  49. 49.
    Z.R. Khayat and T.A. Palmer: Mater. Sci. Eng. A, 2018, vol. 718, pp. 123–34.CrossRefGoogle Scholar
  50. 50.
    J.A. Slotwinski, E.J. Garboczi, and K.M. Hebenstreit: J. Res. Natl. Inst. Stand. Technol., 2014, vol. 119, pp. 494–528.CrossRefGoogle Scholar
  51. 51.
    A. Kisasoz, A. Karaaslan, and Y. Bayrak: Met. Sci. Heat Treat., 2016, vol. 58, pp. 9–12.Google Scholar
  52. 52.
    ASTM E562: Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count, ASTM International, West Conshohocken, PA, 2011.Google Scholar
  53. 53.
    S.D. Meredith, J.S. Zuback, J.S. Keist, and T.A. Palmer: Mater. Sci. Eng. A, 2018, vol. 738, pp. 44–56.CrossRefGoogle Scholar
  54. 54.
    ASTM E975: Standard Practice for X-Ray Determination of Retained Austenite in Steel with Near Random Crystallographic Orientation, ASTM International, West Conshohocken, PA, 2013.Google Scholar
  55. 55.
    T.A. Palmer, J.W. Elmer, and J. Wong: Sci. Technol. Weld. Join., 2002, vol. 7, pp. 159–71.CrossRefGoogle Scholar
  56. 56.
    T.A. Palmer, J.W. Elmer, and S.S. Babu: Mater. Sci. Eng. A, 2004, vol. 374, pp. 307–21.CrossRefGoogle Scholar
  57. 57.
    Z. Zhang, H. Jing, L. Xu, Y. Han, G. Li, and L. Zhao: J. Mater. Eng. Perform., 2017, vol. 26, pp. 134–50.CrossRefGoogle Scholar
  58. 58.
    J. Nilsson: Mater. Sci. Technol., 1992, vol. 8, pp. 685–700.CrossRefGoogle Scholar
  59. 59.
    S. Atamert and J.E. King: Zeitschrift für Met., 1991, vol. 82, pp. 230–9.Google Scholar
  60. 60.
    V. Manvatkar, A. De, and T. DebRoy: Mater. Sci. Technol., 2015, vol. 31, pp. 924–30.CrossRefGoogle Scholar
  61. 61.
    Z. Zhang, H. Jing, L. Xu, Y. Han, L. Zhao, and J. Zhang: Appl. Surf. Sci., 2017, 394, pp. 297–314.CrossRefGoogle Scholar
  62. 62.
    Y. Guo, T. Sun, J. Hu, Y. Jiang, L. Jiang, and J. Li: Alloy. Compd., 2016, vol. 658, pp. 1031–40.CrossRefGoogle Scholar
  63. 63.
    A.J. Ramirez, S.D. Brandi, and J.C. Lippold: Sci. Technol. Weld. Join., 2004, vol. 9, pp. 301–13.CrossRefGoogle Scholar
  64. 64.
    Z. Zhang, H. Jing, L. Xu, Y. Han, and L. Zhao: Corros. Sci., 2017, 120, pp. 194–210.CrossRefGoogle Scholar
  65. 65.
    E. Hämäläinen, A. Laitinen, H. Hänninen, and J. Liimatainen: Mater. Sci. Technol., 1997, vol. 13, pp. 103–9.CrossRefGoogle Scholar
  66. 66.
    A. Laitinen and H. Hanninen: Corrosion, 1996, vol. 52, pp. 295–306.CrossRefGoogle Scholar
  67. 67.
    B.M. Morrow, T.J. Lienert, C.M. Knapp, J.O. Sutton, M.J. Brand, R.M. Pacheco, V. Livescu, J.S. Carpenter, and G.T. Gray: Metall. Mater. Trans. A, 2018, 49, pp. 3637-3650.CrossRefGoogle Scholar
  68. 68.
    E.C. Bain and H.W. Paxton: Alloying Elements in Steel, American Society for Metals, Metals Park, Ohio, 1966.Google Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2019

Authors and Affiliations

  1. 1.Department of Material Science and EngineeringThe Pennsylvania State UniversityUniversity ParkUSA
  2. 2.Applied Research LaboratoryThe Pennsylvania State UniversityUniversity ParkUSA
  3. 3.Department of Engineering Science and MechanicsThe Pennsylvania State UniversityUniversity ParkUSA

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