Evolution of microstructure and texture in Ti-46Al-9Nb sheet material during tensile flow at elevated temperatures

Microstructure and texture evolution as well as phase transformations in Ti-46Al-9Nb sheet material tensile tested between 700 and 1000 degrees C have been analyzed. Up to similar to 850 degrees C the microstructure shows characteristic deformation features such as mechanical twins and deformation bands. The texture, presented as inverse pole figures, contains pure deformation components, i.e. < 001 >, < 111 > and similar to < 301 >. Above 900 degrees C dynamic recrystallization becomes the dominant process. Bulged grain boundaries can clearly be distinguished in the microstructure of the tensile specimens, and the pure deformation orientation maxima < 001 > and < 301 > disappears from the texture map in favor of a new recrystallization component around < 100 >. Under constant temperature conditions the size of dynamically recrystallized grains is influenced by the applied strain rate. Under certain test conditions a alpha 2 ->omega/B82 phase transformation can be observed. This process is enhanced by stress and depends strongly on temperature and time or strain rate. (C) 2010 Elsevier Ltd. All rights reserved.