Understanding the Role of β Recrystallization on β Microtexture Evolution in Hot Processing of a Near-β Titanium Alloy (Ti-10V-2Fe-3Al)

The present study evaluated the beta recrystallization behavior and deformation microtexture evolution of TB6 titanium alloy (Ti-10V-2Fe-3Al) taking place during isothermal compression. The hot deformation tests were carried out in the temperature range below the beta phase transition temperature and spanned a wide strain rate range of 0.0001 similar to 1 s(-1). Microstructure evolution on beta phase, including its recrystallization behavior and microtexture formation, is sensitive to the strain rates, whereas the average grain size of equiaxed alpha phase exhibits a slight increase with the strain rate decreasing. Moreover, beta recrystallization is not homogeneous among the prior beta grains, and is characterized by: (I) enriched beta sub-grains, (II) sporadically or chain-like distributed recrystallized beta grains with a grain size far less than the prior beta grains, and (III) wave-shaped beta grain boundaries. The beta recrystallization is inadequate and its orientation takes on the inheritance characteristic, which makes the beta microtexture significant after deformation. At a lower strain rate, the high activity of the {11-2}< 111 > and {12-3}< 111> slip systems induced the crystal rotation around < 101 >, but such crystal rotation did not destroy the Burgers orientation relationship (BOR), which could be accounted for by the generation of a strong microtexture of < 001 >//RD. The divergences on beta recrystallization fraction, the operation of slip systems, and initial crystal orientations explain the different microtexture components with varied intensities under different deformation conditions.