New insights into the microstructural evolution of Ti-5Al-5Mo-5V-3Cr alloy during hot working

Microstructural features resulting from thermomechanical treatment of the 5-metastable Ti-5Al-5Mo-5V-3Cr (Ti-5553) alloy were studied by means of electron backscatter diffraction and X-ray diffraction. The alloy was deformed at 950 degrees C (beta field) and 800 degrees C (alpha + beta field) with strain rates of 0.001 s(-1) and 0.1 s(-1) in compression mode up to a compression ratio of 0.5 (true ratio = 0.7). It was concluded that beta phase undergoes dynamic recovery both above and below its beta-transus temperature, and recovery is more dominant at lower strain rates, which was corroborated by EBSD misorientation measurements. Meanwhile, alpha phase undergoes not only a process of breakage and globularization, but also decomposition, which contributes to flow softening. The increase in strain rate caused non-uniform recovery at 950 degrees C and a more intense refinement of alpha precipitates at 800 degrees C. Macrotexture evaluation after deformation indicates that beta's texture is much stronger than that of alpha, with its (200) component being the strongest one.