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

Abstract

Microstructure and texture evolution as well as phase transformations in Ti–46Al–9Nb sheet material tensile tested between 700 and 1000 °C have been analyzed. Up to not, vert, similar850 °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 not, vert, similar<301>. Above 900 °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 α2 → ω/B82 phase transformation can be observed. This process is enhanced by stress and depends strongly on temperature and time or strain rate.