Constitutive modeling and processing map for elevated temperature flow behaviors of a powder metallurgy titanium aluminide alloy

Abstract

The flow behaviors of PM titanium aluminide alloy were studied by isothermal compression simulation test. The apparent activation energy of deformation was calculated to be 313.53 kJ mol −1 and a constitutive equation had been established to describe the flow behavior. Processing map was developed at a strain of 0.7. With an increase of strain, two domains can be found: dynamic recrystallization and superplastic deformation, which are further confirmed by microstructural observations. The dynamic recrystallization occurs extensively at 1000 °C and 10 −3 s −1, with a peak efficiency of 50%, and the superplastic deformation occurs at 1100 °C and 10 −3 s −1, with a peak efficiency of 60%. At a strain rate higher than 10 −1 s −1, the alloy exhibits flow instability.