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Development and study of nanostructured titanium alloys with enhanced fatigue properties
|Irina Semenova , Georgy Raab , Ruslan Z. Valiev|
Institute of Physics of Advaced Materials, Ufa State Aviation Technical University (IPAM USATU), 12 K. Marx st., Ufa 450000, Russian Federation
Titanium and titanium based alloys are among the most widespread structural materials applied in various spheres of engineering and medicine. However the problem of enhancement of their mechanical and fatigue properties still remains the issue of the day which we resolve by means of nanostructuring of metals and alloys through severe plastic deformation (SPD) techniques .
The objects of our research are commercially pure titanium and its alloys, Ti-6Al-4V and Ti-6Al-7Nb. The principles of nanostructure formation in the titanium materials by SPD processing are discussed in the present report. SPD processing of titanium billets included equal channel angular pressing (ECAP) in combination with conventional methods of thermomechanical treatment (TMT). Among them are various regimes of extrusion, rolling combined with annealing and strain-heat treatments in conditions of superplasticity.
For example, homogeneous ultrafine-grained (UFG) structure with a grain size less than 400 nm has been formed in the billets from Ti-6Al-4V alloy produced by combined SPD processing . As a result of grain refinement, the strength of up to 1400 MPa and endurance limit on the basis of 107 cycles constituting no less than 700 MPa have been achieved.
The present report demonstrates the possibility of producing pilot articles from UFG titanium materials for applications in medicine and considers the advantages of the articles over the standard products.
 R.Z. Valiev, Nanostructuring of Metals by Severe Plastic Deformation for Advanced Properties, Nature Materials, Vol. 3, pp. 511-516 (2004).
 I.P. Semenova, G.I. Raab, L.R. Saitova, R.Z. Valiev, The effect of equal-channel angular pressing on the structure and mechanical behavior of Ti–6Al–4V alloy, Mater. Sci. Eng., A 387-389 (2004) p. 805-808.
Presentation: Oral at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Irina Semenova
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-14 13:48 Revised: 2009-06-07 00:44