The Effect of Hydrogen on Dynamic Recrystallization in α-Titanium Alloys

Abstract:

The influence of hydrogen content on the mechanical properties and size of dynamically recrystallized grains in commercially pure (CP) titanium and Ti-5Al-2.5Sn alloy was investigated. The alloys with hydrogen contents from 0.1 to 5.2 at.% were deformed in the a-field at temperatures of 650°, 750°С with initial strain rates of 5×10-4 s-1. A decrease of the deformation temperature leads to a reduction in grain size and to a stress increase for all compositions. This is in good agreement with the well known relation between the recrystallized grain size (d) and the steady flow stress ss=kd-n. At a given test temperature the steady state flow stress is four times lower and the grain size is about ten times greater in CP titanium in comparison with the Ti-5Al- 2.5Sn alloy. Hydrogen alloying of the Ti-5Al-2.5Sn alloy does not lead to a noticeable change in ss and d. However, an increase in hydrogen content from 0.1 to 5.2 at.% in CP titanium leads not only to a decrease in grain size by a factor of 2 but also to a decrease in flow stress (about 28%). This result is not in agreement with the above relation. This unusual behaviour may be due to two reasons: the influence of hydrogen on grain growth and the hydrogen effect on dynamic strain ageing. Both these effects are stronger in CP titanium.

• Periodical: Materials Science Forum (Volumes 467-470)
• Pages: 1223-1228
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.467-470.1223
• Online since: October 2004
• Authors: Maria A. Murzinova, Gennady A. Salishchev, D.D. Afonichev
• Keywords: Dynamic Recrystallization (DRX), Hydrogen Solution, α-Titanium Alloys

References

[1] O.N. Senkov, J.J. Jonas and F.H. Froes: JOM (1996) July, pp.42-47.

[2] V.K. Nosov, S.B. Belova, I.N. Chesnokov: Metals, No. 6 (1995) pp.76-82 (in Russian).

[3] O.N. Senkov and J.J. Jonas: Metal. & Mater. Trans. A, V. 27 (1996) May, pp.1303-1312.

[4] O.N. Senkov and J.J. Jonas: Metal. & Mater. Trans. A, V. 27 (1996) July, pp.1877-1887.

[5] O.N. Senkov and J.J. Jonas: Metal. & Mater. Trans. A, V. 27 (1996) December, pp.3963-3970.

[6] H. Yoshimura, K. Kimura, M. Hayashi, M. Ishii,T. Hanamura and J. Takamura: Mater. Trans., JIM, Vol. 35. No. 4 (1994) April, pp.266-272.

[7] M.A. Murzinova, M.I. Mazurski, G.A. Salishchev and D.D. Afonichev: Int. J. Hydrogen Energy, Vol. 22, No. 2/3 (1997), pp.201-204.

[8] S.Z. Bokshtein, S.S. Ginzburg, E.N. Nazarova, V.G. Nefedov: J. Physical Chemistry, No. 5, (1981), pp.1269-1273.

[9] U. Zwicker. Titan und Titanlegierungen. (Springer-Verlag Berlin. Heidelberg. New York. 1974).

[10] R. Boyd: The Science, Technology and Application of Titanium. Pergamon Press. Oxford. (1970), pp.545-556.