Effects of Dislocation Density and Concentration of Vacancies on Growth of O-Phase in Ti2AlNb-Based Alloy

The effects of the dislocation density and of the concentration of vacancies in the β-solid solution on the processes of aging of intermetallic titanium alloy VTI-4 yielding a Ti2AlNb orthorhombic O-phase are studied. It is shown that the influence of the nonequilibrium concentration of vacancies in the solid solution is decisive for acceleration of the diffusion process and abrupt growth of the sizes of the O-phase. Preliminary deformation is shown to have a favorable effect on the deceleration of growth of the O-phase under subsequent aging.

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  1. 1.

    We are obliged to S. A. Naprienko and S. I. Pakhomkin for the SEM and DSC studies.


  1. 1.

    E. N. Kablov, “New-generation materials: a base for innovations, technological leadership and national safety of Russia,” Intellekt Tekhnol., No. 2(14), 16 – 21 (2016).

  2. 2.

    C. Leyens and M. Peters (eds.), Titanium and Titanium Alloys: Fundamental Applications, Wiley-VCH Verlag GmbH&Co, Weinheim (2003), 513 p.

    Google Scholar 

  3. 3.

    W. Chen, J. W. Li, L. Xu, and B. Lu, “Development of Ti2AlNb alloys: opportunities and challenges,” Adv. Mater. Proc., 172, 23 – 27 (2014).

    CAS  Google Scholar 

  4. 4.

    V. V. Antipov, “Prospects of development of aluminum, magnesium and titanium alloys for aircraft and spacecraft engineering,” Aviats. Mater. Tekhnol., No. S, 186 – 194 (2017) (https://doi.org/10.18577/2071-9140-2017-0-S-186-194).

  5. 5.

    E. N. Kablov, “Materials and chemical technologies for aircraft engineering,” Herald Russian Acad. Sci., 82(3), 158 – 167 (2012) (https://doi.org/10.1134/s1019331612030069).

    Article  Google Scholar 

  6. 6.

    E. N. Kablov, N. A. Nochovnaya, P. V. Panin, et al., “A study of the structure and properties of refractory alloys based on titanium aluminide with microadditions of gadolinium,” Materialovedenie, No. 3, 3 – 10 (2017).

  7. 7.

    W. Wang,W. Zeng, Y. Liu, et al., “Microstructural evolution and mechanical properties of Ti – 22Al – 25Nb (at.%) orthorhombic alloy with three typical microstructures,” J. Mater. Eng. Perform., No. 1, 293 – 303 (2018).

  8. 8.

    W. Wang, W. Zeng, C. Xue, et al., “Microstructure control and mechanical properties from isothermal forging and heat treatment of Ti – 22Al – 25Nb (at.%) orthorhombic alloy,” Intermetallics, 56, 79 – 86 (2015).

    CAS  Article  Google Scholar 

  9. 9.

    A. V. Novak, E. B. Alekseev, V. I. Ivanov, and D. A. Dzunovich, “Investigation of the effect of quenching parameters on the structure and hardness of intermetallic titanium ortho-alloy VTI-4,” Trudy VIAM, No. 2(62), 38 – 46 (2018) (URL: http://www.viam-works.ru (äàòà îáðàùåíèÿ 08.03.2020). https://doi.org/10.18577/2307-6046-2018-0-2-5-5).

  10. 10.

    M. A. Gorbovets and N. A. Nochovnaya, “Effect of microstructure and phase composition of refractory titanium alloys on the rate of growth of fatigue crack,” Trudy VIAM, No. 4(40), 21 – 31 (2016) (https://doi.org/10.18577/2307-6046-2016-0-4-3-3).

  11. 11.

    E. B. Alekseev, N. A. Nochovnaya, A. V. Novak, and P. V. Panin, “Deformable intermetallic titanium ortho-alloy with yttrium addition. Part 2. A study of the effect of heat treatment on microstructure and mechanical properties of a rolled plate,” Trudy VIAM, No. 2(62), 37 – 45 (2018) (URL: http://www.viam-works.ru (access date 07.03.2020). https://doi.org/10.18577/2307-6046-2018-0-12-37-45).

  12. 12.

    S. R. Dey, S. Suwas, J. J. Fundenberger, and R. K. Ray, “Evolution of crystallographic texture and microstructure in the orthorhombic phase of a two-phase alloy Ti – 22Al – 25Nb,” Intermetallics, 17, 622 – 633 (2009).

    CAS  Article  Google Scholar 

  13. 13.

    Y. Wang, Z. Lu, K. Zhang, and D. Zhang, “Thermal mechanical processing effects on microstructure evolution and mechanical properties of the sintered Ti – 22Al – 25Nb alloy,” Materials, 9, 189 (2016) (https://doi.org/10.3390/ma9030189).

    CAS  Article  Google Scholar 

  14. 14.

    W. Wang,W. Zeng, D. Li, et al., “Microstructural evolution and tensile behavior of Ti2AlNb alloys based α2-phase decomposition,” Mater. Sci. Eng., 662, 120 – 128 (2016).

    CAS  Article  Google Scholar 

  15. 15.

    S. J. Yang, S. Woo, Nama, and M. Hagiwara, “Phase identification and effect of W on the microstructure and micro-hardness of Ti AlNb-based intermetallic alloys,” J. Alloys Compd., 350, 280 – 287 (2003).

  16. 16.

    Y. Zhang, Q. Cai, Z. Ma, et al., “Solution treatment for enhanced hardness in Mo-modified Ti2AlNb-based alloys,” J. Alloys Compd., 805, 1184 – 1190 (2019).

    CAS  Article  Google Scholar 

  17. 17.

    H. Zhang, Li, Z. Ma, et al., “Static coarsening behavior of a pre-deformed Ti2AlNb-based alloy during heat treatment,” Vacuum, 169, Art. 108934 (2019).

  18. 18.

    B. Shao, Y. Zong, D. Wen, et al., “Investigation of the phase transformations in Ti – 22Al – 25Al alloy,” Mater. Charact., 114, 75 – 78 (2016).

    CAS  Article  Google Scholar 

  19. 19.

    Y. Wua, D. Z. Yang, and G. M. Song, “The formation of mechanism of the O phase in a Ti3Al – Nb alloy,” Intermetallics, 8, 629 – 632 (2000).

    Article  Google Scholar 

  20. 20.

    Y. H. Wen, Y. Wang, L. A. Bendersky, and L. Q. Chen, “Microstructural evolution during the α2 → α2 + O transformation in Ti – Al – Nb alloys: phase-field simulation and experimental validation,” Acta Mater., 48, 4125 – 4135 (2000).

    CAS  Article  Google Scholar 

  21. 21.

    A. A. Tsvetaev (ed.), Defects in Hardened Metals, Mater. Int. Conf., Argon National Laboratory, 15 – 17 June, 1964 [in Russian], Atomizdat, Moscow (1969).

  22. 22.

    I. I. Novikov and K. M. Rozin, Crystallography and Crystal Lattice Defects [in Russian], Metallurgiya, Moscow (1990), 336 p.

  23. 23.

    L. Levin and A. Katsman, “On the problem of high-rate reactive diffusion,” Mater. Chem. Phys., 53, 73 – 76 (1998).

    CAS  Article  Google Scholar 

  24. 24.

    T. Ando and A. Houshmand, “Dislocation climb rate at very high vacancy concentrations,” Materialia, 8, Art. 100472 (2019).

  25. 25.

    T. T. Lau, X. Lin, S. Yip, and K. J. Vliet, “Atomistic examination of the unit processes and vacancy-dislocation interaction in dislocation climb,” Scr. Mater., 60, 399 – 402 (2009).

    CAS  Article  Google Scholar 

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The work has been performed within the grant for “Investigation of Phase Transformations in Refractory Titanium Intermetallic Alloy under the Conditions of Dynamic Loading at Elevated Temperatures” (mol_a_18-33-001189) financed by the Russian Foundation for Fundamental Sciences.

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Correspondence to A. V. Zavodov.

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Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 13 – 17, October, 2020.

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Zavodov, A.V., Medvedev, P.N. & Nochovnaya, N.A. Effects of Dislocation Density and Concentration of Vacancies on Growth of O-Phase in Ti2AlNb-Based Alloy. Met Sci Heat Treat 62, 609–614 (2021). https://doi.org/10.1007/s11041-021-00612-w

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Key words

  • dislocation density
  • vacancies
  • nonequilibrium concentration
  • aging
  • O-phase
  • Ti2AlNb
  • alloy VTI-4
  • hot deformation
  • retrogression