Skip to main content
SpringerLink
Log in

Microstructure and microsegregation of directionally solidified Ti–45Al–8Nb alloy with different solidification rates

  • Published:
Rare Metals Aims and scope Submit manuscript

Abstract

Microstructure and microsegregation of directionally solidified Ti–45Al–8Nb alloy were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron probe microanalyzer (EPMA). For the alloy solidified at the solidification rates (v) ranging from 10 to 400 μm·s−1, the microstructure of the mushy zone exhibits a cellular-dendritic structure at lower growth rate (v = 10–50 μm·s−1) and a typical dendritic morphology at higher growth rate (v = 100–400 μm·s−1). The relationship between primary dendrite arm spacing (λ 1) and v is λ 1 = 1.08 × 103 v −0.35. Al and Nb elements segregate at interdendritic zone and in the dendritic core, respectively. In solid of mushy zone, a relatively flat concentration profile is observed for the typical dendrite structure, and Nb enriches in B2 phase induced by β → α + β transformation. The content of B2 phase is hardly affected by v. The extent of microsegregation in steady-state zone decreases at a lower growth rate because holding the samples at higher temperature after solidification for a long time can homogenize the solid effectively.

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

Access this article

Log in via an institution

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

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  1. Liu ZC, Lin JP, Li SJ, Chen GL. Effects of Nb and Al on the microstructures and mechanical properties of high Nb containing TiAl base alloys. Intermetallics. 2002;10(7):653.

    Article  Google Scholar 

  2. Lin JP, Xu XJ, Wang YL, He SF, Zhang Y, Song XP, Chen GL. High temperature deformation behaviors of a high Nb containing TiAl alloy. Intermetallics. 2007;15(5–6):668.

    Article  Google Scholar 

  3. Li JB, Liu Y, Liu B, Wang Y, Liang XP, He YH. Microstructure characterization and mechanical behaviors of a hot forged high Nb containing PM-TiAl alloy. Mater Charact. 2014;95:148.

    Article  Google Scholar 

  4. Xu XJ, Lin JP, Han DD. Effect of Al on microstructures and properties of Ti–45Al–8.5Nb–0.2B–0.2W alloy. Mater Sci Forum. 2013;44:747.

    Google Scholar 

  5. Song L, Zhang LQ, Xu XJ, Sun J, Lin JP. Omega phase in as-cast high-Nb-containing TiAl alloy. Scr Mater. 2013;68(12):929.

    Article  Google Scholar 

  6. Huang ZW, Voice W, Bowen P. Thermal exposure induced α2+γ → B2(ω) and α2 → B2(ω) phase transformations in a high Nb fully lamellar TiAl alloy. Scr Mater. 2003;48(1):79.

    Article  Google Scholar 

  7. Tang B, Cheng L, Kou HC, Li JS. Hot forging design and microstructure evolution of a high Nb containing TiAl alloy. Intermetallics. 2015;58(12):7.

    Article  Google Scholar 

  8. Bolz S, Oehring M, Lindemann J, Pyczak F, Paul J, Stark A, Lippmann T, Schrüfer S. Microstructure and mechanical properties of a forged β-solidifying γ TiAl alloy in different heat treatment conditions. Intermetallics. 2015;58(3):71.

    Article  Google Scholar 

  9. Schloffer M, Rashkova B, Schöberl T, Schwaighofer E, Zhang ZL, Clemens H, Mayer S. Evolution of the ωo phase in a β-stabilized multi-phase TiAl alloy and its effect on hardness. Acta Mater. 2014;64(2):241.

    Article  Google Scholar 

  10. Lapin J, Gabalcová Z. Solidification behaviour of TiAl-based alloys studied by directional solidification technique. Intermetallics. 2011;19(6):797.

    Article  Google Scholar 

  11. Zollinger J, Gabalcová Z, Daloz D, Lapin J, Combeau H. Microsegregation induced microstructures in intermetallic Ti–46Al–8Nb alloy. Kovove Mater. 2008;46(5):291.

    Google Scholar 

  12. Liu Y, Hu R, Kou HC, Wang J, Zhang TB, Li JS, Zhang J. Solidification characteristics of high Nb-containing c-TiAl-based alloys with different aluminum contents. Rare Met. 2015;34(6):381.

    Article  Google Scholar 

  13. Battel T. Mathematical modeling of solute segregation in solidifying materials. Int Mater Rev. 1992;37(6):249.

    Article  Google Scholar 

  14. Ganesan M, Dye D. A technique for characterizing microsegregation in multicomponent alloys and its application to single-crystal superalloy castings. Metall Mater Trans A. 2005;36(8):2191.

    Article  Google Scholar 

  15. Zhang C, Ma D, Kou S, Chang YA, Yan XY. Microstructure and microsegregation in directionally solidified Mg–4Al alloy. Intermetallics. 2007;15(10):1395.

    Article  Google Scholar 

  16. Fan JL, Li XZ, Su YQ, Chen RR, Guo JJ, Fu HZ. Directional solidification of Ti–49 at.%Al alloy. Appl Phys A. 2011;105(1):239.

    Article  Google Scholar 

  17. Kurz W, Fisher DJ. Fundamentals of Solidification. Aedermannsdorf, Switzerland: Trans Tech Publications Ltd.; 1992. 295.

    Google Scholar 

  18. Witusiewicza VT, Bondarb AA, Hechta U, Velikanova T. The Al–B–Nb–Ti system: IV. Experimental study and thermodynamic re-evaluation of the binary Al–Nb and ternary Al–Nb–Ti systems. J Alloys Compd. 2009;472(1–2):133.

    Article  Google Scholar 

  19. Santos RG, Melo MLNM. Permeability of interdendritic channels. Mater Sci Eng A. 2005;391:151.

    Article  Google Scholar 

  20. Giovanola B, Kurz W. Modeling of microsegregation under rapid solidification conditions. Metall Trans A. 1990;21(1):260.

    Article  Google Scholar 

  21. Ding XF, Lin JP, He JP, Ye F, Chen GL. Directional solidification of Ti–45Al–8Nb–(W, B, Y) alloy. Rare Met. 2010;29(3):292.

    Article  Google Scholar 

  22. Kim MC, Oh MH, Lee JH, Inui H, Yamaguchi M, Wee DM. Composition and growth rate effects in directionally solidified TiAl alloys. Mater Sci Eng A. 1997;239–240:570.

    Article  Google Scholar 

Download references

Acknowledgments

This study was financially supported by the National Natural Science Foundation of China (Nos. U1204508 and 51271016) and the National Basic Research Program of China (No. 2011CB605501).

Author information

Authors and Affiliations

  1. Materials and Chemistry School, Zhongyuan University of Technology, Zhengzhou, 450007, China

    Xiang-Jun Xu

  2. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China

    Lin Song, Dong-Dong Han, Xin Wang & Jun-Pin Lin

  3. School of Architecture and Engineering, Heilongjiang University, Harbin, 150080, China

    Xiao-Ou Jin

Authors
  1. Xiang-Jun Xu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Lin Song
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Xiao-Ou Jin
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Dong-Dong Han
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Xin Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Jun-Pin Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jun-Pin Lin.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Xu, XJ., Song, L., Jin, XO. et al. Microstructure and microsegregation of directionally solidified Ti–45Al–8Nb alloy with different solidification rates. Rare Met. 35, 70–76 (2016). https://doi.org/10.1007/s12598-015-0635-x

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12598-015-0635-x

Keywords

Search

Navigation