Effect of hot forging in the ordered phase field on microstructure and mechanical properties of β-solidifying γ-TiAl alloys

V.M. Imayev, A.A. Ganeev, T.I. Nazarova, R.M. Imayev show affiliations and emails
Received 25 September 2019; Accepted 09 October 2019;
Citation: V.M. Imayev, A.A. Ganeev, T.I. Nazarova, R.M. Imayev. Effect of hot forging in the ordered phase field on microstructure and mechanical properties of β-solidifying γ-TiAl alloys. Lett. Mater., 2019, 9(4s) 528-533
BibTex   https://doi.org/10.22226/2410-3535-2019-4-528-533


The picture illustrates a significant microstriucture change in the cast Ti-44Al-5Nb-0.2B alloy after upset forging with a low strain value followed by heat treatment.Effect of hot forging at lower temperatures, in the α2+γ+βo / α2+γ phase fields, followed by heat treatment on the microstructure and tensile properties has been studied for three β-solidifying γ-TiAl alloys. The alloy compositions were Ti-45Al-5Nb-1Mo-0.2B, Ti-43.7Al-4.2Nb-0.5Mo-0.2C-0.2B and Ti-44Al-5Nb-0.2B (at. %). The phase transformation sequences were defined for the alloys. Hot forging procedure for the Ti-45Al and Ti-43.7Al based alloys included forging in the temperature range of the α+γ+β(βo)/α+α2+γ+β(βo) and α2+γ+βo phase fields. This led to refined microstructures due to occurrence of dynamic recrystallization and globularization processes. The as-forged alloys showed excellent superplastic properties. Particularly, superior superplastic properties (El>>1000% and low flow stresses), never reached in γ-TiAl alloys, were obtained for the Ti-43.7Al based alloy in the temperature range of 900-1000ºC. The Ti-44Al based alloy was only forged to a small strain in the temperature range of the α2+γ phase field. All forged alloys were further subjected to two-stage annealing in the α+γ+β(βo) and α2+γ+βo or α2+γ phase fields. As a result, refined duplex microstructures were obtained in the alloys. Tensile tests were performed for the forged and heat treated alloys. They showed quite reasonable tensile properties as compared with those obtained in similar alloys after high-temperature hot forging followed by heat treatment. Particularly, the Ti-45Al-5Nb-0.2B alloy in the duplex condition exhibited El=3.1% and UTS=860 MPa at room temperature and El=6.5% and UTS= 790 MPa at 700ºC.

References (21)

1. B. P. Bewlay, M. Weimer, T. Kelly, A. Suzuki, P. R. Subramanian. In: Intermetallic-based alloys - science, technology and applications (ed. by I. Baker, M. Heilmaier, S. Kumar, K. Yoshimi). Warrendale (PA), TMS, MRS 1516 (2013) pp. 49 - 58. Crossref
2. H. Clemens, S. Mayer. Adv. Eng. Mater. 15, 191 (2013). Crossref
3. V. Küstner, M. Oehring, A. Chatterjee, V. Güther, H.-G. Brokmeier, H. Clemens, et al. In: Gamma titanium aluminides 2003 (ed. by Y.-W. Kim, H. Clemens, A. H. Rosenberger). Warrendale (PA), TMS (2003) pp. 89 - 96.
4. Y. Jin, J. N. Wang, J. Yang, Y. Wang. Scr. Mater. 51, 113 (2004). Crossref
5. R. M. Imayev, V. M. Imayev, M. Oehring, F. Appel. Intermet. 15, 451 (2007). Crossref
6. H. Clemens, W. Wallgram, S. Kremmer, V. Güther, A. Otto, A. Bartels. Adv. Eng. Mater. 10, 707 (2008). Crossref
7. D. Hu, H. Jiang, X. Wu. Intermet. 17, 744 (2009). Crossref
8. S. Bolz, M. Oehring, J. Lindemann, F. Pyczak, J. Paul, A. Stark, T. Lippmann, S. Schrüfer, D. Roth-Fagaraseanu, A. Schreyer, S. Weiß. Intermet. 58, 71 (2015). Crossref
9. N. Z. Niu, Y. Y. Chen, F. T. Kong, J. P. Lin. Intermet. 31, 249 (2012). Crossref
10. Y. Su, F. Kong, Y. Chen, N. Gao, D. Zhang. Intermet. 34, 29 (2013). Crossref
11. E. Schwaighofer, H. Clemens, J. Lindemann, A. Stark, S. Mayer. Mater. Sci. Eng. A. 614, 297 (2014). Crossref
12. F. Appel, M. Oehring, J. D. H. Paul. Adv. Eng. Mater. 8, 371 (2006). Crossref
13. J. D. H. Paul, U. Lorenz, M. Oehring, F. Appel. Intermet. 32, 318 (2013). Crossref
14. W. Xu, X. Jin, K. Huang, Y. Zong, S. Wu, X. Zhong, F. Kong, D. Shan, S. Nutt. Mater. Sci. Eng. A. 705, 200 (2017). Crossref
15. V. M. Imayev, R. M. Imayev, T. I. Oleneva, T. G. Khismatullin. Phys. Met. & Metallogr. 106 (6), 641 (2008). Crossref
16. T. I. Nazarova, V. M. Imayev, R. M. Imayev, R. R. Mulyukov. Phys. of Met. & Metallogr. 117 (10), 1038 (2016). Crossref
17. V. M. Imayev, A. A. Ganeev, R. M. Imayev. Intermet. 101, 81 (2018). Crossref
18. V. M. Imayev, R. M. Imayev, T. G. Khismatullin, T. I. Oleneva, V. Gühter, H.-J. Fecht. Mater. Sci. Forum. 638 - 642, 235 (2010). Crossref
19. V. M. Imayev, T. G. Khismatullin, R. M. Imayev. Phys. of Metals & Metallogr. 109 (4), 402 (2010). Crossref
20. E. Schwaighofer, B. Rashkova, H. Clemens, A. Stark, S. Mayer. Intermet. 46, 173 (2014). Crossref
21. V. M. Imayev, R. M. Imayev, T. I. Nazarova, R. A. Gaisin, A. A. Ganeev. Letters on Materials. 8 (4s), 554 (2018). Crossref

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1. The work was supported by the State Assignment of the Institute for Metals Superplasticity Problems of the Russian Academy of Sciences. - No. AAAA-A17-117041310215-4