Ti-6Al-4V (Ti-64) is one of the most widely used α+β titanium alloys in the aerospace industry due to its low density, high strength-to-weight ratio and excellent corrosion resistance. During processing, Ti64 undergoes a series of deformation and heat treatments in the α+β temperature window, during which recrystallization and phase transformation during and following deformation generates characteristic crystallographic texture, which is often heterogeneous and highly detrimental to mechanical performance. In an effort to better understand the relative contribution of recrystallization and phase transformation to texture development, we have carried out an in-situ EBSD experiment using an SEM equipped with a heating stage and a high-speed EBSD detector, which can effectively capture the rapid changes during heating and cooling.

In this study, a Ti64 alloy was hot rolled at 850°C to 75% reduction, and then examined using EBSD to measure the macro and micro texture. A through thickness map revealed a strong transverse texture (0002//TD) and a weak basal texture (0002//ND) after hot rolling. The sample was then in-situ heated in a Tescan SEM, and EBSD maps were taken simultaneously from 800°C to 1000°C as well as during cooling. The 150×200μm scanning area has two macrozones with distinct textures, strong 0002//TD and weak 0002//ND, corresponding to the main texture components after rolling. After heating, the orientation gradient in alpha grains from rolling was eliminated, and alpha and beta textures in both regions were strengthened. Moreover, the alpha phase was found recrystallizing rapidly from 860°C to 920°C but quickly transformed into the beta phase with a further temperature increase. Surprisingly, during the early stage of heating, beta grains with cube orientation {001}<100> recrystallized in both macrozones and rapidly grew into large grains when they reached 970°C. These measurements suggest that recrystallization in both phases could be an important mechanism in the texture development during the processing of these important alloys.