Influence of Annealing Time on Local Texture Evolution in Forged Ti–6Al–4V Alloy

The α + β titanium alloy Ti–6Al–4V is extensively used in the aero-engine components such as turbine blades and discs where the service temperature is less (<300 °C). These parts are mainly fabricated by the thermomechanical processing under the isothermal condition. A microstructure inhomogeneities (or local texture) can be observed after the secondary processing such as closed die forging. The origin of the inhomogeneities is believed to be the microstructure development stage only, and it persists even after the secondary processing. Such inhomogeneities in the forged component such as the turbine blade may cause crack initiation under the fatigue loading. Therefore, the primary processing is paid more attention to develop a homogenous microstructure. With the advent of advanced material characterization techniques such as electron backscatter diffraction (EBSD), the microstructure inhomogeneities have been recently characterized. In this study, two specimens were sectioned out from the different locations of the forged part, exhibiting different levels of inhomogeneities. These specimens were heat-treated for varying periods, and the influence of annealing time on the local texture evolution has been characterized using EBSD.