Enhancement of TiZr ductility by hcp-fcc martensitic transformation after severe plastic deformation

In the present paper we identify by x-ray diffraction and electron microscopy the athermal formation of the fcc phase, which is beneficial for a high ductility in TiZr, after severe plastic deformation (SPD) at an ambient temperature. For true strains e >= 2.2, the lattice distortions increase, favoring more martensitic formation of the fcc phase. This coincides with the enhancement of the ductility which is attributed to the higher number of slip systems in the fcc phase than in the hcp phase. (C) 2013 Elsevier B.V. All rights reserved.