Texture development in Ti-6Al-4V linear friction welds

Microstructure and microtexture development in as-welded and post weld heat treated (PWHT) lab-scale (LS) and full-scale (FS) Ti-6Al-4V linear friction welds have been characterized using scanning electron microscopy and electron back-scatter diffraction (EBSD). The full-scale specimens exhibited a plastically affected zone (PAZ) about twice the size compared to lab-scale test welds. At the weld line a region of very fine martensitically formed microstructure was observed in both the LS and FS friction welds. EBSD texture scans across the weld line revealed a sharp texture variation in the PAZ. At the weld line a strong {1010}< 1120 > transverse texture for the as-welded and PWHTed condition was observed in both welds. Whereas the lab-scale linear friction welds displayed a dramatic change from almost random to strong transverse texture in the PAZ, the full-scale linear friction welds exhibited transverse texture at the weld line, followed by dispersed bands of transverse and {1122} < 1123 > type rolling texture in the PAZ region. The observed difference in LS and FS weld region textures is attributed to a difference in the variant selections during beta -> alpha transformation. (C) 2007 Elsevier B.V. All rights reserved.