Phase transformation and dynamic recrystallization behaviors in a Ti55511 titanium alloy during hot compression

Hot compression experiments of a Ti55511 titanium alloy are conducted to study the phase transformation characteristics and dynamic recrystallization (DRX) behavior. It is found that the fraction of alpha phase decreases with increasing the strain rate or deformation amount. Meanwhile, the original lamellar alpha phases easily transform into the spheroidal and bulk a phases at larger deformation amounts or higher strain rates. Most of alpha phases disappear and the final microstructures are mainly beta phases when the temperature is over 800 degrees C. The DRX degree rises with raising the deformation amount or decreasing the strain rate. However, the DRX behavior becomes weaken with raising the deformation temperature. alpha phases are evenly distributed around beta phases during hot compressive deformation, which not only restrains the growth of beta phases but also promotes the DRX process of beta phases. In addition, the geometric DRX takes place within alpha phases, while the continuous DRX occurs within beta phases during the hot compression. (C) 2019 Elsevier B.V. All rights reserved.