Influence of Alloying Elements in Fatigue Properties of α/β Titanium Alloys


Article Preview

One strategy to make PM titanium components competitive in terms of mechanical properties is the addition of suitable alloying elements. PM offers the possibility to adapt the alloy composition in order to achieve the required properties. In this study, different alloying elements were introduced into α/β titanium alloys and fatigue behaviour was evaluated. Four-point bending fatigue tests with a stress ratio of 0.2 were performed on specimens manufactured by metal injection moulding (MIM) and shot peening. Results showed an enhanced sintering activity of Ti-6Al-7Nb by adding small amounts of iron. The impact on fatigue properties was evaluated. The increase of oxygen in Ti-6Al-7Nb from 0.15 wt.% to 0.45 wt.% caused a decrease in elongation from 16% to 6%. However the fatigue strength at 107 cycles is just slightly reduced from 450 to 350 MPa. The addition of 0.5 wt.% yttrium powder to gas atomized Ti‑6Al‑4V powder led to a noticeable refinement of the microstructure of the sintered parts, due to the formation of Y2O3 particles, which hinder grain growth. In spite of a slightly higher residual porosity, the microstructural refinement increased the fatigue strength at 107 cycles from 450 to 470 MPa. At 106 cycles, the fatigue strength increased even from 705 to 765 MPa. The addition of yttrium did not result in a higher oxygen pick up, which indicates a scavenging of oxygen from the titanium matrix by formation of Y2O3 during sintering. Contrary to the fatigue strength results, the scavenging effect led to a decrease in tensile strength of about 70 MPa. The microstructure of fatigue-tested specimens was characterized by using optical and scanning electron microscopy.



Edited by:

Huiping Tang, Ma Qian, Yong Liu, Peng Cao and Gang Chen




A. A. Hidalgo et al., "Influence of Alloying Elements in Fatigue Properties of α/β Titanium Alloys", Key Engineering Materials, Vol. 770, pp. 80-86, 2018

Online since:

May 2018




* - Corresponding Author

[1] H. R. Ogden and R. I. Jaffee, The effects of carbon, oxygen, and nitrogen on the mechanical properties of titanium and titanium alloys,, Titanium Metallurgical Laboratory, Battelle Memorial Institute Columbus 1, Ohio, 20, Oct. (1955).


[2] H. Miura, The influence of density and oxygen content on the mechanical properties of injection molded Ti-6Al-4V alloys,, Adv. Powder Metall. Part. Mater. - 2010 Proc. 2010 Int. Conf. Powder Metall. Part. Mater., p.446–453, (2010).

[3] T. Ebel, O. Milagres Ferri, W. Limberg, M. Oehring, F. Pyczak, and F. P. Schimansky, Metal Injection Moulding of Titanium and Titanium-Aluminides,, in Powder Metallurgy of Titanium, Australia, 2012, vol. 520, p.153–160.


[4] A. Amherd Hidalgo, T. Ebel, W. Limberg, and F. Pyczak, Influence of oxygen on the fatigue behaviour of Ti-6Al-7Nb alloy,, in Powder Metallurgy of Titanium II, 2016, vol. 704, p.44–52.


[5] P. G. Esteban, L. Bolzoni, E. M. Ruiz-Navas, and E. Gordo, PM processing and characterisation of Ti–7Fe low cost titanium alloys,, Powder Metall., vol. 54, no. 3, p.242–252, Jul. (2011).


[6] Y. Liu, L. F. Chen, H. P. Tang, C. T. Liu, B. Liu, and B. Y. Huang, Design of powder metallurgy titanium alloys and composites,, Mater. Sci. Eng. A, vol. 418, no. 1–2, p.25–35, Feb. (2006).


[7] E. Pereloma, D. Savvakin, A. Carman, A. Gazder, and O. Ivasishin, Microstructure development and alloying elements diffusion during sintering of near-beta titanium alloys,, in Powder Metallurgy of Titanium, Brisbane, Australia, 2012, vol. 520, p.49.


[8] O. M. Ferri, Optimisation of Fatigue Behaviour of Ti-6Al-4V Alloy Components Fabricated by Metal Injection Moulding,, PhD thesis, Technische Universität Hamburg-Harburg, (2010).

[9] M. Yan, Y. Liu, G. B. Schaffer, and M. Qian, In situ synchrotron radiation to understand the pathways for the scavenging of oxygen in commercially pure Ti and Ti–6Al–4V by yttrium hydride,, Scr. Mater., vol. 68, no. 1, p.63–66, Jan. (2013).


[10] W. Limberg, T. Ebel, and K.U. Kainer, Addition of rare earth elements to MIM - processed Ti6Al4V,, in Euro PM 2014, Salzburg, Austria, (2014).

[11] A. Amherd Hidalgo et al., Fundamental Understanding of the Influence of Oxygen on the Fatigue behaviour of Ti-6Al-7Nb Alloys,, in World PM 2016, Hamburg (Germany), (2016).

[12] N.G. Turner and W.T. Roberts, Fatigue behavior of titanium,, Trans Met Soc AIME, vol. 242, p.1223–1230, (1968).

[13] C. Leyens and M. Peters, Eds., Titanium and titanium alloys. Wiley-VCH, (2003).

[14] H. Nakajima, Koiwa, M., and Ono, S., Diffusion of iron in single crystal alpha-titanium,, Scr. Metall., vol. 17, p.1431–1434, (1983).


[15] W. Limberg and T. Ebel, Metal Injection Moulding of Ti-6Al-4V with Yttrium addition,, Key Eng. Mater., p.20–27, (2016).


[16] W. Limberg, T. Ebel, and F. Pyczak, Colony Refinement of MIM-processed Ti-6Al-4V by Addition of Different Yttrium Compounds,, presented at the World PM 2016, Hamburg, (2016).

[17] T. Ebel, Friederici, V., Imgrund, P., and Hartwig, T., Metal Injection Moulding of Titanium,, in Titanium Powder Metallurgy, Boston: Butterworth-Heinemann, 2015, p.337–360.