Micro-texture of extruded Zr-2.5Nb tubes

We report the micro-texture of two extruded Zr-2.5Nb tubes determined using scanning electron microscopy combined with electron back-scattering diffraction (SEM/EBSD) and transmission electron microscopy and selected area diffraction (TEM/SAD). The pole figures determined by SEM/EBSD correspond well with bulk pole figures previously determined by X-ray diffraction (XRD). Three components of texture are seen to correlate with the shape and morphology of the alpha-grains and their contained dislocation substructures. The first component corresponds to elongated alpha grains containing a high density of a and c + a dislocations in which the c-axis is oriented at a relatively high angle to the long dimension of the alpha-grains as viewed in transverse section; these grains comprise a texture component with the c-axes in the radial transverse plane, tilted towards the radial direction. The second component corresponds to elongated alpha-grains containing a low dislocation density in which the c-axis is oriented parallel to the long dimension of the alpha grains: these grains also comprise a texture component with the c-axis in the radial/transverse plane, but predominantly in the transverse direction. The final component corresponds to colonies of Widmanstdtten-like alpha-grains that are transformed from the beta-phase: the majority of these grains have their c-axes in the axial direction. These grain have very low dislocation densities and are probably developed during cooling, after extrusion. Crown Copyright (C) 2004 Published by Elsevier B.V. All rights reserved.