Experimental Mechanics

, Volume 50, Issue 6, pp 717–724 | Cite as

Thermomechanical Fatigue of the TiAl Intermetallic Alloy TNB-V2

  • T. K. HeckelEmail author
  • H.-J. Christ


TiAl is supposed to substitute Ni or Ti alloys in energy conversion systems, such as aero engines. These components are subjected to thermomechanical fatigue (TMF), whereas this mechanical behaviour may substantially differ from isothermal low cycle fatigue (LCF). Therefore, it is necessary to assess TMF properties, in order to establish a reliable and precise lifetime prediction model. In this study the γ-base TiAl intermetallic alloy TNB-V2 was subjected to fully-reversed TMF tests under total strain control at strain amplitude of 0.7%, accompanied by LCF tests in air and vacuum. Temperature ranged from 550°C to 850°C. In TMF tests a continuous built-up of compressive (in-phase) or tensile (out-of-phase) mean stresses is observed. The lifetime ratio between IP and OP is 30–200, depending on temperature range. Substantially longer lifetimes of OP-TMF tests in vacuum are observed. Fracture always occurs in a transcrystalline mode. A lifetime description at 550°C based on the Basquin-Coffin-Manson equation reveals that the fatigue behaviour is governed by the amount of elastic strain even at low cycles, and the transition lifetime was found to be at 5 cycles. A damage parameter based on the equation of Smith, Watson and Topper is able to describe LCF and in-phase TMF lifetimes reasonably.


Titanium aluminides Thermomechanical fatigue Environmental effects Lifetime description Smith-Watson-Topper equation 



Financial support for this work by Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged. The authors would also like to thank their project partner for providing the material and performing complementary investigations (Dr. F. Appel and his research group, GKSS Research Centre, Geesthacht, Germany).


  1. 1.
    Appel F, Lorenz U, Paul JDH, Oehring M (1999) The mechanical properties of niobium alloyed gamma titanium aluminides. In: Kim Y-W, Dimiduk DM, Loretto MH (eds) Gamma titanium aluminides 1999. TMS, Warrendale, pp 381–388Google Scholar
  2. 2.
    Roth M, Biermann H (2008) Thermo-mechanical fatigue behaviour of a modern γ-TiAl alloy. Int J of Fatigue 30:352–356. doi: 10.1016/j.ijfatigue.2007.01.049 zbMATHGoogle Scholar
  3. 3.
    Bauer V, Christ H-J (2009) Thermomechanical fatigue behaviour of a third generation TiAl intermetallic alloy. Intermetallics 17:370–377. doi: 10.1016/j.intermet.2008.11.013 CrossRefGoogle Scholar
  4. 4.
    Brookes SP, Kühn HJ, Skrotzki B, Sievert R, Pfetzing J, Eggeler G (2007) Axial-torsional thermo-mechanical fatigue of Ti-45Al-5Nb-0.2B-0.2C. In: Niinomi M, Akiyama S, Hagiwara M, Ikeda M, Maruyama K (eds) Ti-2007 science and technology, vol. 1. The Japan Institute of Metals, Sendai, pp 679–682Google Scholar
  5. 5.
    Christ H-J (2007) Effect of environment on thermomechanical fatigue life. Mat Sci Eng A 468–470:98–108. doi: 10.1016/j.msea.2006.08.132 CrossRefGoogle Scholar
  6. 6.
    Appel F, Wagner R (1998) Microstructure and deformation of two-phase γ-titanium aluminides. Mat Sci Eng R 22:187–268CrossRefGoogle Scholar
  7. 7.
    Sastry SML, Lipsitt HA (1977) Fatigue deformation of TiAl alloys. Met Trans A 8:299–308CrossRefGoogle Scholar
  8. 8.
    Christ HJ, Fischer FOR, Maier HJ (2001) High-temperature fatigue behavior of a near-γ titanium aluminide alloy under isothermal and thermo-mechanical conditions. Mat Sci Eng A 319–321:625–630. doi: 10.1016/S0921-5093(00)02013-X CrossRefGoogle Scholar
  9. 9.
    Jouiad M, Gloanec A-L, Grange M, Hénaff G (2005) Cyclic deformation mechanisms in a cast gamma titanium aluminide. Mat Sci Eng A 400–401:409–412CrossRefGoogle Scholar
  10. 10.
    Srivatsan TS, Soboyejo WO, Strangwood M (1995) Cyclic fatigue and fracture behavior of a gamma-titanium aluminide intermetallic. Eng Frac Mech 52:107–120CrossRefGoogle Scholar
  11. 11.
    Appel F, Heckel TK, Christ H-J (2009) Electron microscope characterization of low cycle fatigue in a high-strength multiphase titanium aluminide alloy, Int J of Fatigue, doi:10.1016/j.ijfatigue.2009.04.001
  12. 12.
    Fröbel U, Appel F (2002) Strain ageing in gamma(TiAl)-based titanium aluminides due to antisite atoms. Acta Mater 50:3693–3707CrossRefGoogle Scholar
  13. 13.
    Mishin Y, Herzig C (2000) Diffusion in the Ti-Al system. Acta Mater 48:589–623CrossRefGoogle Scholar
  14. 14.
    Venkateswara Rao KT, Kim Y-W, Muhlstein CL, Ritchie RO (1995) Fatigue-crack growth and fracture resistance of a two-phase (γ+α2) TiAl alloy in duplex and lamellar microstructures. Mat Sci Eng A 192/193:474–482. doi: 10.1016/0921-5093(94)03264-5 CrossRefGoogle Scholar
  15. 15.
    Nickel H, Zheng N, Elschner A, Quadakkers WJ (1995) The oxidation behaviour of niobium containing γ-TiAl intermetallics in air and argon/oxygen. Mikrochim Acta 119:23–39Google Scholar
  16. 16.
    Yoshihara M, Kim Y-W (2005) Oxidation behavior of gamma alloys designed for high temperature applications. Intermetallics 13:952–985. doi: 10.1016/j.internet.2004.12.007 CrossRefGoogle Scholar
  17. 17.
    Chan KS, Kim Y-W (1991) Fracture processes in a two-phase gamma titanium aluminide alloy. In: Kim Y-W, Boyer RR (eds) Microstructure / property relationships in titanium aluminides and alloys. TMS, Warrendale, pp 179–196Google Scholar
  18. 18.
    Malakondaiah G, Nicholas T (1996) High-temperature low-cycle fatigue of gamma titanium aluminide alloy Ti-46Al-2Nb-2Cr. Met Mat Trans A 27:2239–2251CrossRefGoogle Scholar
  19. 19.
    Park YS, Nam SW, Hwang SK, Kim NJ (2002) The effect of the applied strain range on fatigue cracking in lamellar TiAl alloy. J Alloys Compd 335:216–223. doi: 10.1016/S0925-8388(01)01812-6 CrossRefGoogle Scholar
  20. 20.
    Hertzberg RW (1976) Deformation and fracture mechanics of engineering materials. John Wiley & Sons, New YorkGoogle Scholar
  21. 21.
    Hoppe R (2008) Personal communication. GKSS Research Centre, GeesthachtGoogle Scholar
  22. 22.
    Smith KN, Watson P, Topper TH (1970) A stress-strain function for the fatigue of metals. J Mater 5:767–778Google Scholar
  23. 23.
    Dowling NE (2007) Mechanical behavior of materials. Pearson Prentice Hall, Upper Saddle RiverGoogle Scholar

Copyright information

© Society for Experimental Mechanics 2009

Authors and Affiliations

  1. 1.Universität Siegen, Institut für WerkstofftechnikSiegenGermany

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