Plastic deformation of a Ti-6% Al-4% V alloy with a strong transverse-type crystallographic alpha-texture at elevated temperatures

The deformation behaviour of (alpha + beta)-Ti with a very sharp texture is influenced by temperature, strain rate and the sense of stress. In this paper the plastic deformation of (alpha + beta)-Ti is investigated in a temperature range between 295 and 1073 K in compression and tension along different directions of the sheet plane (0 degrees, 45 degrees and 90 degrees from the rolling direction (RD)). For this temperature range, two phenomena are observed: a dynamic strain ageing (DSA) and a asymmetry of the yield stress associated with the movement of [c + a] dislocations. Electron microscopy of specimens strained in uniaxial tension or compression along [0001] at 570 K shows [c + a] dislocations moving on {1 (1) over bar 01} and {11 (2) over bar 2} planes and an anomalous activity of [c + a] dislocations is observed On the whole range of orientation. We discuss the effect of interstitial solutes on the activity of the [c + a] dislocations between 500 and 750 K and the effect of the non-centrosymmetry for the {11 (0) over bar 1} planes on the directional asymmetry of the yield stress associated with the [c + a] movement. (C) 1997 Elsevier Science S.A.