Texture heterogeneities in alpha/alpha titanium forging analysed by EBSD-relation to fatigue crack propagation.
The microstructure and the local texture of a large IMI 834 forging were characterized using the Electron Back Scattered Diffraction (EBSD) technique. Crystallographic domains called macrozones and formed by a majority of primary alpha(p) grains with their axes in nearly the same direction were found. They had a band-like structure, parallel to the axial direction of the forging. The influence of these macrozones on the cold dwell-fatigue properties was studied. Several samples were tested under cold dwell-fatigue conditions. The crack initiation and the short-distance propagation region optically matched a bright region that contained numerous quasi-cleavage facets. The analysis of the EBSD measurements showed that this bright region was enclosed within a sharp textured region with axes at less than 30 degrees from the loading axis. The crystallographic features of the crack nucleation site and the crack propagation path were also analysed.
Uta
E
E
Laboratoire d'Etude des Textures et Applications aux Matériaux (LETAM), CNRS UMR 7078, Université de Metz, 57045 Metz Cedex 01, France.
Gey
N
N
Bocher
P
P
Humbert
M
M
Gilgert
J
J