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Investigation on the homogenization treatment and element segregation on the microstructure of a γ/γ′-cobalt-based superalloy

  • Saeed Aliakbari Sani
  • Hossein ArabiEmail author
  • Shahram Kheirandish
  • Golamreza Ebrahimi
Article

Abstract

The aim of the present study was to investigate the effect of element segregation on the microstructure and γ′ phase in a γ/γ′ cobalt- based superalloy. Several samples were prepared from a cast alloy and homogenized at 1300°C for different times, with a maximum of 24 h. A microstructural study of the cast alloy using wavelength-dispersive spectroscopic analysis revealed that elements such as Al, Ti, and Ni segregated mostly within interdendritic regions, whereas W atoms were segregated within dendrite cores. With an increase in homogenization time, segregation decreased and the initial dendritic structure was eliminated. Field-emission scanning electron microscopy micrographs showed that the γ′ phases in the cores and interdendritic regions of the as-cast alloy were 392 and 124 nm, respectively. The size difference of γ′ was found to be due to the different segregation behaviors of constituent elements during solidification. After homogenization, particularly after 16 h, segregation decreased; thus, the size, chemical composition, and hardness of the precipitated γ′ phase was mostly uniform throughout the samples.

Keywords

superalloy segregation homogenization microstructure γ′ phase 

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Notes

Acknowledgement

The authors would like to appreciate the support of Dr. Jahanafrooz for this research.

References

  1. [1]
    V.A. Wills and D.G. McCartney, A comparative study of solidification features in nickel-base superalloys: Microstructural evolution and microsegregation, Mater. Sci. Eng. A, 145(1991), No. 2, p. 223.CrossRefGoogle Scholar
  2. [2]
    N. Warnken, D. Ma, A. Drevermann, R.C. Reed, S.G. Fries, and I. Steinbach, Phase-field modelling of as-cast microstructure evolution in nickel-based superalloys, Acta Mater., 57(2009), No. 19, p. 5862.CrossRefGoogle Scholar
  3. [3]
    G.D. Merz, T.Z. Kattamis, and A.F. Giamei, Microsegration and homogenization of Ni-7.5wt%Al-2.0wt%Ta dendritic monocrystals, J. Mater. Sci., 14(1979), No. 3, p. 663.CrossRefGoogle Scholar
  4. [4]
    M.S.A. Karunaratne, D.C. Cox, P. Carter, and R.C. Reed, Modelling of the microsegregation in CMSX-4 superalloy and its homogenisation during heat treatment, Superalloys, 2000, p. 263.Google Scholar
  5. [5]
    Z.J. Miao, A.D. Shan, Y.B. Wu, J. Lu, W.l. Xu, and H.W. Song, Quantitative analysis of homogenization treatment of INCONEL718 superalloy, Trans. Nonferrous Met. Soc. China, 21(2011), No. 5, p. 1009.CrossRefGoogle Scholar
  6. [6]
    Y.J. Li, Y.F. Teng, X.H. Feng, and Y.S. Yang, Effects of pulsed magnetic field on microsegregation of solute elements in a Ni-based single crystal superalloy, J. Mater. Sci. Technol., 33(2017), No. 1, p. 105.CrossRefGoogle Scholar
  7. [7]
    J.B. le Graverend, J. Cormier, P. Caron, S. Kruch, F. Gallerneau, and J. Mendez, Numerical simulation of γ/γ′ microstructural evolutions induced by TCP-phase in the MC2 nickel base single crystal superalloy, Mater. Sci. Eng. A, 528(2011), No. 6, p. 2620.CrossRefGoogle Scholar
  8. [8]
    A.S. Golezani, M. Bageri, and R. Samadi, Microstructural change, and impact toughness property of Inconel 738LC after 12 years of service, Eng. Fail. Anal., 59(2016), p. 624.CrossRefGoogle Scholar
  9. [9]
    M.R. Jahangiri, S.M.A. Boutorabi, and H. Arabi, Study on incipient melting in cast Ni base IN939 superalloy during solution annealing and its effect on hot workability, Mater. Sci. Technol., 28(2012), No. 12, p. 1402.CrossRefGoogle Scholar
  10. [10]
    S.H. Fu, J.X. Dong, M.C. Zhang, and X.S. Xie, Alloy design and development of INCONEL718 type alloy, Mater. Sci. Eng. A, 499(2009), No. 1–2, p. 215.CrossRefGoogle Scholar
  11. [11]
    Y.Z. Zhou and A. Volek, Effect of carbon additions on hot tearing of a second generation nickel-base superalloy, Mater. Sci. Eng. A, 479(2008), No. 1–2, p. 324.CrossRefGoogle Scholar
  12. [12]
    C.N. Wei, H.Y. Bor, and L. Chang, The effects of carbon content on the microstructure and elevated temperature tensile strength of a nickel-base superalloy, Mater. Sci. Eng. A, 527(2010), No. 16–17, p. 3741.CrossRefGoogle Scholar
  13. [13]
    F. Long, Y.S. Yoo, C.Y. Jo, S.M. Seo, Y.S. Song, T. Jin, and Z.Q. Hu, Formation of η and σ phase in three polycrystalline superalloys and their impact on tensile properties, Mater. Sci. Eng. A, 527(2009), No. 1–2, p. 361.CrossRefGoogle Scholar
  14. [14]
    J. Zhang and R.F. Singer, Effect of Zr and B on castability of Ni-based superalloy IN792, Metall. Mater. Trans. A, 35(2004), No. 4, p. 1337.CrossRefGoogle Scholar
  15. [15]
    A. Epishin, T. Link, U. Brückner, B. Fedelich, and P. Portella, Effects of segregation in nickel-base superalloys: Dendritic stresses, Superalloys, 2004, p. 537.Google Scholar
  16. [16]
    P. Li, S.S. Li, and Y.F. Han, Influence of solution heat treatment on microstructure and stress rupture properties of a Ni3Al base single crystal superalloy IC6SX, Intermetallics, 19(2011), No. 2, p. 182.CrossRefGoogle Scholar
  17. [17]
    M.T. Kim, D.S. Kim, and O.Y. Oh, Effect of γ′ precipitation during hot isostatic pressing on the mechanical property of a nickel-based superalloy, Mater. Sci. Eng. A, 480(2008), No. 1–2, p. 218.CrossRefGoogle Scholar
  18. [18]
    D.L. Sponseller, Differential thermal analysis of nickel-base superalloys, Superalloys, 1996, p. 259.Google Scholar
  19. [19]
    D.A. Porter and K.E. Easterling, Phase Transformations in Metals and Alloys, 2nd Ed., CRC Press, State of Florida, 1992, p. 61.CrossRefGoogle Scholar
  20. [20]
    F.J. Humphreysand M. Hatherly, Recrystallization and Related Annealing Phenomena, Elsevier, The Netherlands, 2004, p. 137.Google Scholar
  21. [21]
    J. Sato, T. Omori, K. Oikawa, I. Ohnuma, R. Kainuma, and K. Ishida, Cobalt-base high-temperature alloys, Science, 312(2006), No. 5770, p. 90.CrossRefGoogle Scholar
  22. [22]
    K. Tanaka, M. Ooshima, N. Tsuno, A. Sato, and H. Inui, Creep deformation of single crystals of new Co-Al-W-based alloys with fcc/L12 two-phase microstructures, Philos. Mag., 92(2012), No. 32, p. 4011.CrossRefGoogle Scholar
  23. [23]
    M.S. Titus, A. Suzuki, and T.M. Pollock, Creep and directional coarsening in single crystals of new γ-γ′ cobalt-base alloys, Scripta Mater., 66(2012), No. 8, p. 574.CrossRefGoogle Scholar
  24. [24]
    F. Xue, H.J. Zhou, X.H. Chen, Q.Y. Shi, H. Chang, M.L. Wang, X.F. Ding, and Q. Feng, Creep behavior of a novel Co-Al-W-base single crystal alloy containing Ta and Ti at 982°C, MATEC Web of Conferences, 14(2014), p. 15002.CrossRefGoogle Scholar
  25. [25]
    A. Bauer, S. Neumeier, F. Pyczak, R.F. Singer, and M. Göken, Creep properties of different γ′-strengthened Co-base superalloys, Mater. Sci. Eng. A, 550(2012), p. 333.CrossRefGoogle Scholar
  26. [26]
    S. Neumeier, L.P. Freund, and M. Göken, Novel wrought γ/γ′ cobalt base superalloys with high strength and improved oxidation resistance, Scripta Mater., 109(2015), p. 104.CrossRefGoogle Scholar
  27. [27]
    A. Suzuki and T.M. Pollock, High-temperature strength and deformation of γ/γ′ two-phase Co-Al-W-base alloys, Acta Mater., 56(2008), No. 6, p. 1288.CrossRefGoogle Scholar
  28. [28]
    M. Tsunekane, A. Suzuki, and T.M. Pollock, Single-crystal solidification of new Co-Al-W-base alloys, Intermetallics, 19(2011), No. 5, p. 636.CrossRefGoogle Scholar
  29. [29]
    X.F. Ding, T. Mi, F. Xue, H.J. Zhou, and M.L. Wang, Microstructure formation in γ-γ′ Co-Al-W-Ti alloys during directional solidification, J. Alloys Compd., 599(2014), p. 159.CrossRefGoogle Scholar
  30. [30]
    E.T. McDevitt, Feasibility of cast and wrought Co-Al-WX gamma-prime superalloys, Mater. Sci. Forum, 783–786(2014), p. 1159.CrossRefGoogle Scholar
  31. [31]
    I. Lopez-Galilea, C. Zenk, S. Neumeier, S. Huth, W. Theisen, and M. Göken, The thermal stability of intermetallic compounds in an as-cast SX Co-base superalloy, Adv. Eng. Mater., 17(2015), No. 6, p. 741.CrossRefGoogle Scholar
  32. [32]
    J. Koßmann, C.H. Zenk, I. Lopez-Galilea, S. Neumeier, A. Kostka, S. Huth, W. Theisen, M. Göken, R. Drautz, and T. Hammerschmidt, Microsegregation and precipitates of an as-cast Co-based superalloy—microstructural characterization and phase stability modelling, J. Mater. Sci., 50(2015), No. 19, p. 6329.CrossRefGoogle Scholar
  33. [33]
    P.J. Bocchini, E.A. Lass, K.W. Moon, M.E. Williams, C.E. Campbell, U.R. Kattner, D.C. Dunand, and D.N. Seidman, Atom-probe tomographic study of γ/γ′ interfaces and compositions in an aged Co-Al-W superalloy, Scripta Mater., 68(2013), No. 8, p. 563.CrossRefGoogle Scholar
  34. [34]
    F. Pyczak, A. Bauer, M. Göken, U. Lorenz, S. Neumeier, M. Oehring, J. Paul, N. Schell, A. Schreyer, A. Stark, and F. Symanzik, The effect of tungsten content on the properties of L12-hardened Co-Al-W alloys, J. Alloys Compd., 632(2015), p. 110.CrossRefGoogle Scholar
  35. [35]
    H.Y. Yan, V.A. Vorontsov, and D. Dye, Alloying effects in polycrystalline γ′ strengthened Co-Al-W base alloys, Intermetallics, 48(2014), p. 44.CrossRefGoogle Scholar
  36. [36]
    K. Shinagawa, T. Omori, J. Sato, K. Oikawa, I. Ohnuma, R. Kainuma, and K. Ishida, Phase equilibria and microstructure on γ′ phase in Co-Ni-Al-W system, Mater. Trans., 49(2008), No. 6, p. 1474.CrossRefGoogle Scholar
  37. [37]
    R.C. Kramb, M.M. Antony, and S.L. Semiatin, Homogenization of a nickel-base superalloy ingot material, Scripta Mater., 54(2006), No. 9, p. 1645.CrossRefGoogle Scholar
  38. [38]
    S.R. Hegde, R.M. Kearsey, and J.C. Beddoes, Designing homogenization-solution heat treatments for single crystal superalloys, Mater. Sci. Eng. A, 527(2010), No. 21–22, p. 5528.CrossRefGoogle Scholar
  39. [39]
    A. Janotti, M. Krčmar, C.L. Fu, and R.C. Reed, Solute diffusion in metals: Larger atoms can move faster, Phys. Rev. Lett., 92(2004), No. 8, p. 85901.CrossRefGoogle Scholar
  40. [40]
    S.S. Naghavi, V.I. Hegde, and C. Wolverton, Diffusion coefficients of transition metals in fcc cobalt, Acta Mater., 132(2017), p. 467.CrossRefGoogle Scholar
  41. [41]
    L. Gong, B. Chen, Z.H. Du, M.S. Zhang, R.C. Liu, and K. Liu, Investigation of solidification and segregation characteristics of cast Ni-base superalloy K417G, J. Mater. Sci. Technol., 34(2016), No. 3, p. 541.CrossRefGoogle Scholar
  42. [42]
    X.L. Pan, H.Y. Yu, G.F. Tu, W.R. Sun, and Z.Q. Hu, Segregation and diffusion behavior of niobium in a highly alloyed nickel-base superalloy, Trans. Nonferrous Met. Soc. China, 21(2011), No. 11, p. 2402.CrossRefGoogle Scholar
  43. [43]
    Y. Minamino, Y. Koizumi, N. Tsuji, T. Yamada, and T. Takahashi, Interdiffusion in Co solid solutions of Co-Al-Cr-Ni system at 1423 K, Mater. Trans., 44(2003), No. 1, p. 63.CrossRefGoogle Scholar
  44. [44]
    S. Obata, M. Moniruzzaman, and Y. Murata, Interdiffusion in Co-based Co-Al-W ternary alloys at elevated temperatures, ISIJ Int., 54(2014), No. 10, p. 2129.CrossRefGoogle Scholar
  45. [45]
    H. Chang, G.L. Xu, X.G. Lu, L. Zhou, K. Ishida, and Y.W. Cui, Experimental and phenomenological investigations of diffusion in Co-Al-W alloys, Scripta Mater., 106(2015), p. 13.CrossRefGoogle Scholar
  46. [46]
    J. Chen, L. Zhang, J. Zhong, W. Chen, and Y. Du, High-throughput measurement of the composition-dependent interdiffusivity matrices in Ni-rich fcc Ni-Al-Ta alloys at elevated temperatures, J. Alloys Compd., 688(2016), p. 320.CrossRefGoogle Scholar
  47. [47]
    S. Neumeier, H.U. Rehman, J. Neuner, C.H. Zenk, S. Michel, S. Schuwalow, J. Rogal, R. Drautz, and M. Göken, Diffusion of solutes in fcc cobalt investigated by diffusion couples and first principles kinetic Monte Carlo, Acta Mater., 106(2016), p. 304.CrossRefGoogle Scholar
  48. [48]
    A. Green and N. Swindells, Measurement of interdiffusion coefficients in Co-AI and Ni-AI systems between 1000 and 1200°C, Mater. Sci. Technol., 1(1985), No. 2, p. 101.CrossRefGoogle Scholar
  49. [49]
    I. Povstugar, P.P. Choi, S. Neumeier, A. Bauer, C.H. Zenk, M. Göken, and D. Raabe, Elemental partitioning and mechanical properties of Ti- and Ta-containing Co-Al-W-base superalloys studied by atom probe tomography and nanoindentation, Acta Mater., 78(2014), p. 78.CrossRefGoogle Scholar
  50. [50]
    I. Povstugar, C.H. Zenk, R. Li, P.P. Choi, S. Neumeier, O. Dolotko, M. Hoelzel, M. Göken, and D. Raabe, Elemental partitioning, lattice misfit and creep behaviour of Cr containing γ′ strengthened Co base superalloys, Mater. Sci. Technol., 32(2016), No. 3, p. 220.CrossRefGoogle Scholar
  51. [51]
    V.A. Vorontsov, J.S. Barnard, K.M. Rahman, H.Y. Yan, P.A. Midgley, and D. Dye, Coarsening behaviour and interfacial structure of γ′ precipitates in Co-Al-W based superalloys, Acta Mater., 120(2016), p. 14.CrossRefGoogle Scholar
  52. [52]
    C.H. Zenk, S. Neumeier, H.J. Stone, and M. Göken, Mechanical properties and lattice misfit of γ/γ′ strengthened Co-base superalloys in the Co-W-Al-Ti quaternary system, Intermetallics, 55(2014), p. 28.CrossRefGoogle Scholar
  53. [53]
    A. Bauer, S. Neumeier, F. Pyczak, and M. Göken, Microstructure and creep strength of different γ/γ′-strengthened Co-base superalloy variants, Scripta Mater., 63(2010), No. 12, p. 1197.CrossRefGoogle Scholar
  54. [54]
    M.J. Donachie and S.J. Donachie, Superalloys: A Technical Guide, ASM international, New York, 2002, p. 82.Google Scholar
  55. [55]
    R.C. Reed, The Superalloys: Fundamentals and Applications, Cambridge University Press, Cambridge, 2008, p. 216.Google Scholar

Copyright information

© University of Science and Technology Beijing and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Saeed Aliakbari Sani
    • 1
  • Hossein Arabi
    • 1
    Email author
  • Shahram Kheirandish
    • 1
  • Golamreza Ebrahimi
    • 2
  1. 1.School of Materials and Metallurgical EngineeringIran University of Science and Technology (IUST)Narmak, TehranIran
  2. 2.Materials and Polymers Engineering DepartmentFaculty of Engineering, Hakim Sabzevari UniversitySabzevarIran

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