Texture Evolution and Associated Nucleation and Growth Mechanisms during Annealing of a Zr Alloy

The evolution of the crystallographic texture in a Zr-2Hf alloy has been followed during deformation, primary recrystallization, and subsequent normal grain growth. The rolling textures (from 50 to 90 pct strain) are constituted of two partial orientation fibers, D-f = {hkil} < 10 (1) over bar0 > and R-f = {hkil} < 11 (2) over bar0 >; along which the two main orientations are the so-called tilted {0001} < 10 (1) over bar0 > and tilted {0001} < 11 (2) over bar0 > texture components for which the {0001} poles are approximately 25 deg away from the specimen normal direction (ND). A decrease in the intensity of the D-f fiber and a continuous increase in the intensity of the R-f fiber take place during primary recrystallization and normal grain growth. An analysis of the neutron diffraction line profiles reveals a stored energy (SE) difference between the main orientations of these two texture fibers after deformation. These observations as well as some considerations about the possible active deformation systems and some partial observations of the nucleation and growth states allow us to propose possible mechanisms to explain the observed texture evolution.