The effect of cooling conditions on Ti 6%Al 4%V microstructure observed using high-temperature in-situ scanning electron microscopy


This study focuses on continuous imaging of microstructural changes in Ti 6% Al 4% V when cooling from the β transus of ~ 995 °C or above. A range of microstructures were obtained by accessing different cooling rates. With cooling rates of 0.1–0.5 °C/s, lamellar microstructures were observed, which initiate in a colony microstructure below temperatures of ~ 930 °C. When the lamellar microstructure began forming at grain boundaries, cooling was interrupted to further observe the kinetics in the system. Lamellae changed in projected length from 40 µm to ~ 160–320 µm over three minutes at ~ 930 °C, within the α + β mixed phase. On further time at temperature, the lengthening of lamellae stagnated. With further cooling at 0.1 °C/s, lamellae grew in projected width, while the projected length remained the same. In addition, a surface topography formed at elevated temperatures (around 800 °C), evolved during the α to β heating transition, and persisted upon cooling.

Graphic abstract

This is a preview of subscription content, access via your institution.

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


  1. 1.

    G. Lütjering, Influence of processing on microstructure and mechanical properties of (α+β) titanium alloys. Mater. Sci. Eng. A. 243, 32–45 (1998)

    Article  Google Scholar 

  2. 2.

    S.L. Semiatin, V. Seetharaman, I. Weiss, Hot workability of titanium and titanium aluminide alloys—an overview. Mater. Sci. Eng. A. 243, 1–24 (2002)

    Article  Google Scholar 

  3. 3.

    Y.T. Lee, M. Peters, G. Welsch, Elastic moduli and tensile and physical properties of heat-treated and quenched powder metallurgical Ti-6Al-4V alloy. Metall. Trans. A. 22, 709–714 (1991)

    Article  Google Scholar 

  4. 4.

    G. Lütjering, Property optimization through microstructural control in titanium and aluminum alloys. Mater. Sci. Eng. A. 263, 117–126 (1999)

    Article  Google Scholar 

  5. 5.

    N. Poondla, T.S. Srivatsan, A. Patnaik, M. Petraroli, A study of the microstructure and hardness of two titanium alloys: Commercially pure and Ti-6Al-4V. J. Alloys Compd. 486, 162–167 (2009)

    CAS  Article  Google Scholar 

  6. 6.

    S.L. Semiatin, S.L. Knisley, P.N. Fagin, F. Zhang, D.R. Barker, Microstructure evolution during alpha-beta heat treatment of Ti-6Al-4V. Metall. Mater. Trans. A 34, 2377–2386 (2003)

    Article  Google Scholar 

  7. 7.

    S. Patil, S. Kekade, K. Phapale, S. Jadhav, A. Powar, A. Supare, R. Singh, Effect of α and β phase volume fraction on machining characteristics of titanium alloy Ti6Al4V. Procedia Manuf. 6, 63–70 (2016)

    Article  Google Scholar 

  8. 8.

    C.J. Boehlert, C.J. Cowen, S. Tamirisakandala, D.J. McEldowney, D.B. Miracle, In situ scanning electron microscopy observations of tensile deformation in a boron-modified Ti–6Al–4V alloy. Scr. Mater. 55, 465–468 (2006)

    CAS  Article  Google Scholar 

  9. 9.

    H. Li, C.J. Boehlert, T.R. Bieler, M.A. Crimp, Analysis of the deformation behavior in tension and tension-creep of Ti-6Al-4V(wt%) at 298K and 728K using in-situ SEM experiments. Philos. Mag. 95, 691–729 (2015)

    CAS  Article  Google Scholar 

  10. 10.

    H. Li, C.J. Boehlert, T. Bieler, M.A. Crimp, Analysis of the deformation behavior in tension and tension-creep of Ti-3Al-25V (wt pct) at 296 K and 728 K (23 °C and 455 °C) using in situ SEM experiments. Metall. Mater. Trans. A 45(13), 6053–6066 (2014)

    CAS  Article  Google Scholar 

  11. 11.

    E. Alabort, D. Putman, R.C. Reed, Superplasticity in Ti-6Al-4V: characterisation, modelling and applications. Acta Mater. 95, 428–442 (2015)

    CAS  Article  Google Scholar 

  12. 12.

    E. Alabort, P. Kontis, D. Barba, K. Dragnevski, R.C. Reed, On the mechanisms of superplasticity in Ti–6Al–4V. Acta Mater. 105, 449–463 (2016)

    CAS  Article  Google Scholar 

  13. 13.

    J.L. Walley, R. Wheeler, M.D. Uchic, M.J. Mills, In-situ mechanical testing for characterizing strain localization during deformation at elevated temperatures. Exp. Mech. 52, 405–416 (2012)

    CAS  Article  Google Scholar 

  14. 14.

    G.A. Kane, D.M. Frey, R. Hull, Influence of controlled cooling rates during thermal processing of Ti 6% Al 4% V alloys using in-situ scanning electron microscopy. MRS Adv. 5, 1603–1611 (2020)

    CAS  Article  Google Scholar 

  15. 15.

    L. Vitos, A.V. Ruban, H.L. Skriver, J. Kollár, The surface energy of metals. Surf. Sci. 411, 186–202 (1998)

    CAS  Article  Google Scholar 

  16. 16.

    G. Bilalbegovic, F. Ercolessi, E. Tosatti, High-temperature surface faceting. Surf. Sci. Lett. 258, L676–L678 (1991)

    CAS  Google Scholar 

  17. 17.

    P. Wynblatt, D. Chatain, Surface segregation anisotropy and equilibrium shape of alloy crystals. Rev Adv Mater Sci. 21, 44 (2009)

    CAS  Google Scholar 

  18. 18.

    E.D. Williams, N.C. Bartelt, Surface faceting and the equilibrium crystal shape. Ultramicroscopy 31, 35–48 (1989)

    Article  Google Scholar 

  19. 19.

    J.R. Heffelfinger, C.B. Carter, Mechanisms of surface faceting and coarsening. Surf. Sci. 389, 188–200 (1997)

    CAS  Article  Google Scholar 

  20. 20.

    R. Narayanan, C. Carter, Bunching of surface steps and facet formation on analumina surface. J. Mater. Res. 17, 98–106 (2002)

    Article  Google Scholar 

  21. 21.

    R. Verre, R.G.S. Sofin, V. Usov, K. Fleischer, D. Fox, G. Behan, H. Zhang, I.V. Shvets, Equilibrium faceting formation in vicinal Al2O3 (0001) surface caused by annealing. Surf. Sci. 606, 1815–1820 (2012)

    CAS  Article  Google Scholar 

  22. 22.

    M.A. Cuddihy, A. Stapleton, S. Williams, F.P.E. Dunne, On cold dwell facet fatigue in titanium alloy aero-engine components. Int. J. Fatigue. 97, 177–189 (2017)

    CAS  Article  Google Scholar 

  23. 23.

    D.A. Brice, P. Samimi, I. Ghamarian, Y. Liu, R.M. Brice, R.F. Reidy, J.D. Cotton, M.J. Kaufman, P.C. Collins, Oxidation behavior and microstructural decomposition of Ti-6Al-4V and Ti-6Al-4V-1B sheet. Corros. Sci. 112, 338–346 (2016)

    CAS  Article  Google Scholar 

  24. 24.

    B. Sefer, Oxidation and alpha–case phenomena in titanium alloys used in aerospace industry: Ti–6Al–2Sn–4Zr–2Mo and Ti–6Al–4V, Lulea University of Technology, (2014).

  25. 25.

    Y. Mizuno, F.K. King, Y. Yamauchi, T. Homma, A. Tanaka, Y. Takakuwa, T. Momose, Temperature dependence of oxide decomposition on titanium surfaces in ultrahigh vacuum. J. Vac. Sci. Technol. A 20, 1716 (2002)

    CAS  Article  Google Scholar 

  26. 26.

    D. Damisih, I. Jujur, J. Sah, D. Prajitno, Effect of heat treatment temperature on microstructure characteristic and hardness properties of casted Ti-6Al-4V ELI. Widyariset. 4, 153–162 (2018)

    Article  Google Scholar 

  27. 27.

    S.L. Semiatin, T.M. Lehner, J.D. Miller, R.D. Doherty, D.U. Furrer, Alpha/beta heat treatment of a titanium alloy with a nonuniform microstructure. Metall. Mater. Trans. A 38, 910–921 (2007)

    Article  Google Scholar 

  28. 28.

    A. Attanasio, M. Gelfi, A. Pola, E. Ceretti, C. Giardini, Influence of Material Microstructures in Micromilling of Ti6Al4V Alloy. Materials (Basel). 6, 4268–4283 (2013)

    CAS  Article  Google Scholar 

  29. 29.

    S. Shademan, V. Sinha, A.B.O. Soboyejo, W.O. Soboyejo, An investigation of the effects of microstructure and stress ratio on fatigue crack growth in Ti-6Al-4V with colony α/β microstructures. Mech. Mater. 36, 161–175 (2004)

    Article  Google Scholar 

  30. 30.

    A.K. Ackerman, A.J. Knowles, H.M. Gardner, A.A.N. Nemeth, I. Bantounas, A. Radecka, M. Moody, P.A.J. Bagot, R. Reed, D. Rugg, D. Dye, The kinetics of primary alpha plate growth in titanium alloys. Metall. Mater. Trans. A. 51, 131–141 (2020)

    CAS  Article  Google Scholar 

  31. 31.

    F.H. Froes, Titanium-physical metallurgy processing, and applications. ASM Int. 20, 32–33 (2015)

    Google Scholar 

  32. 32.

    N. Stanford, P.S. Bate, Crystallographic variant selection in Ti-6Al-4V. Acta Mater. 52, 5215–5224 (2004)

    CAS  Article  Google Scholar 

  33. 33.

    J. Tao, S. Hu, L. Ji, Effect of micromorphology at the fatigue crack tip on the crack growth in electron beam welded Ti-6Al-4V joint. Mater. Charact. 120, 185–194 (2016)

    CAS  Article  Google Scholar 

  34. 34.

    R.K. Nalla, B.L. Boyce, J.P. Campbell, J.O. Peters, R.O. Ritchie, Influence of microstructure on high-cycle fatigue of Ti-6Al-4V: Bimodal vs lamellar structures. Metall. Mater. Trans. A 33, 899–918 (2002)

    Article  Google Scholar 

  35. 35.

    Tiley, J. Modeling of Microstructure Property Relationships in Ti-6Al-4V. Ph.D. Dissertation, The Ohio State University 2002

  36. 36.

    Kammrath and Weiss GmbH (2015).

  37. 37.

    R. Heard, J.E. Huber, C. Siviour, G. Edwards, E. Williamson-Brown, K. Dragnevski, An investigation into experimental in situ scanning electron microscope (SEM) imaging at high temperature. Rev. Sci Inst. 91, 063702 (2020)

    CAS  Article  Google Scholar 

Download references


We acknowledge the sponsorship of the National Science Foundation, through CMMI-1647005 (equipment design and construction) and CMMI-1729336 (in-situ experimentation in Ti 6-4) awards for funding this work, as well as the use of characterization and cleanroom facilities within the Center for Materials, Devices and Integrated Systems at Rensselaer Polytechnic Institute. We acknowledge Brent Engler for useful discussions on lamellar growth. In addition, we acknowledge Konrad Weiss, Farhad Ghaleh, and George Lanzarotta from Kammrath and Weiss GmbH., for their expertise and assistance with equipment development.

Author information



Corresponding author

Correspondence to Robert Hull.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kane, G.A., Andersen, D., Frey, M.D. et al. The effect of cooling conditions on Ti 6%Al 4%V microstructure observed using high-temperature in-situ scanning electron microscopy. Journal of Materials Research (2021).

Download citation


  • Microstructural evolution
  • Surface faceting
  • Phase change kinetics
  • Lamellar growth
  • Scanning electron microscopy