Machines. Technologies. Materials.
Vol. 15 (2021), Issue 8, pg(s) 309-310

MATERIALS

Utrafine-grained structure and thermal stability of the two-phase titanium alloy VT8M-1

  • 1 Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx str., Ufa 450008, Russia

Abstract

In this work, the method of backscattered electron diffraction (EBSD) and transmission electron microscopy (TEM) was used for microstructural analysis of the improved VT8M-1 alloy (Ti-5.7 Al-3.8 Mo-1.2 Zr-1.3 Sn) subjected to equal-channel angular pressing (ECAP) and rotary forging (RF). It was found that the process of globularization induced during deformation processing is regulated by the conventional boundary-splitting mechanism. It was shown that an orientation relation is established between the spheroidized a – and bphases. This result is achieved due to the high activity of dislocation sliding at the boundary of the a-and b-phases. The thermal stability of the VT8M-1 alloy with an ultrafine-grained (UFG) structure is s -term (up to 500 hours) annealing the UFG structure is thermally stable. The mechanical properties and the effect of annealing on the microstructure are discussed. It is shown that particles of the Ti-Zr-Si system are isolated at the interphase boundaries.

Keywords

References

  1. G. Lütjering, J. C. Williams, Titanium, Springer, Berlin, Heidelberg, 2007, p. 335.
  2. R. Z. Valiev, Y. Estrin, Z. Horita, T. G. Langdon, M. J. Zehetbauer, & Y. Zhu, Producing bulk ultrafine-grained materials by severe plastic deformation: ten years later. Jom, 68(4), (2016) 1216-1226.
  3. R.S. Mishra, V.V. Stolyarov, C. Echer, R.Z. Valiev, A.K. Mukherjee, Mechanical behavior and superplasticity of a severe plastic deformation processed nanocrystalline Ti–6Al–4V alloy, Mater. Sci. Eng. A 298 (2001) 44-50.
  4. I.P. Semenova, E.B. Yakushina, V.V. Nurgaleeva, R.Z. Valiev, Nanostructuring of Ti-alloys by SPD processing to achieve superior fatigue properties, Int. J. Mater. Res. 100 (2009) 1691-1696.
  5. S.L. Semiatin, P.N. Fagin, J.F. Betten, A.P. Zane, A.K. Ghosh, G.A. Sargent, Plastic flow and microstructure evolution during low-temperature superplasticity of ultrafine Ti-6Al-4V sheet material, Metall. Mater. Trans. A 41 (2010) 499–512.
  6. S.V. Zherebtsov, E.A. Kudryavtsev, G.A. Salishchev, B.B. Straumal, S.L. Semiatin, Microstructure evolution and mechanical behavior of ultrafine Ti-6Al-4V during low temperature superplastic deformation, Acta Mater. 121 (2016) 152–163.
  7. A.A. Popov, M.O. Leder, M.A. Popova, N.G. Rossina, I.V. Narygina, Effect of alloying on precipitation of intermetallic phases in heat-resistant titanium alloys, The physics of metals and metallography. 116 (2015) 261-266.
  8. A. Popov, M.A. Zhilyakova, O. Elkina, K.I. Lugovaya, The Precipitation of Silicide Particles in Heat-Resistant Titanium Alloys, in: S. Syngellakis, J. J. Connor (Eds.), Advanced Methods and Technologies in Metallurgy in Russia, Springer International Publishing AG, Switzerland, 2018, pp. 19-25.
  9. Singh A. K., Characterization of silicides in high-temperature titanium alloys / A. K. Singh, C. Ramachandra // Journal of materials science.1997. V.32. P.229-234.

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