Dynamic Softening Mechanisms and Microstructure Evolution of TB18 Titanium Alloy during Uniaxial Hot Deformation

In this study, isothermal compression tests of TB18 titanium alloy were conducted using a Gleeble 3800 thermomechanical simulator for temperatures ranging from 650 to 880 °C and strain rates 0.001 10 s−1, with constant height reduction 60%, investigate the dynamic softening mechanisms hot workability alloy. The results showed that flow stress significantly decreased an increasing deformation temperature decreasing rate, which was affected by competition between work hardening softening. hyperbolic sine Arrhenius-type constitutive equation established, activation energy calculated be 303.91 kJ·mol−1 in (α + β) phase zone 212.813 β zone. processing map constructed at true 0.9 exhibited stability instability regions under tested conditions. microstructure characteristics demonstrated region, dominant restoration flow-softening recovery globularization α grains below transus temperature, as well continuous recrystallization above temperature. mechanism localization form shear band caused adiabatic heating.