Nanoscale mechanism and intrinsic structure related deformation of Ti-alloys

A series of Ti-Nb-Ta-(In/Cr) and Ti-Fe-(Sn) alloys containing a bcc beta-Ti phase with a grain size ranging from the nanometer/ultrafine regime to the micrometer scale has been prepared by slow cooling from the melt. The plastic deformation behavior has been investigated under compression and the deformation-induced microstructure evolution was checked by X-ray diffraction, scanning and transmission electron microscopy. The data reveal that the underlying mechanisms related to plasticity or brittleness of the P-phase depends significantly on the supersaturation, the local lattice strain, the ease of dislocation slip, as well as twinning and diffusionless transformation triggering grain refinement. The intrinsic structure, the short-range order and the stability of the beta-Ti phase have a strong influence on the mode of plastic deformation of the investigated Ti-alloys. (c) 2007 Elsevier B.V. All rights reserved.