Flow Behavior and Constitutive Model of a β-γ TiAl-Based Alloy Under Hot Deformation

The flow behavior of a TNM alloy was evaluated in the high-temperature compression tests. The constitutive models for the flow curves and dynamic recrystallization were constructed to predict stress-strain and microstructure variations. The flow behavior of a Ti-43Al-4Nb-1Mo-0.2B alloy was studied by employing hot compression tests within a temperature range of 1000–1200°C and strain rates of 0.001–0.1 s^-1. The flow stress of the alloy was gradually going down with temperature and strain rate decrease, and dynamic recrystallization was the main softening mechanism. The peak shape evolution indicated that recrystallization occurred preferentially at high temperatures and low strain rates. The constitutive model for the flow behavior of the alloy was constructed with the fifth-order polynomial fitting method. Additionally, simulation of the volume fraction and grain sizes in recrystallization was effected. All the models demonstrated a good fit with the experimental results.