Superplasticity and hot rolling of two-phase intermetallic alloy based on TiAl

Abstract

The deformation behavior in the isothermal compression of Ti-46.5Al–2Nb–2Cr (at. %) including flow stress and microstructure evolution at the deformation temperatures ranging from 1373 to 1533 K and strain rates from 0.001 to 1 s−1 were investigated. The phenomenological-based model was established by describing the variation of the strain hardening exponent with the increasing of strain. The strain rate sensitivity exponent ranging from 0.065 to 0.449 indicated the transition of deformation mechanism from dislocation creep to grain boundary sliding, and the model by considering the effect of the processing parameters on the strain rate sensitivity was presented. The effect of the processing parameters on the apparent activation energy for deformation was analyzed. Furthermore, the novel constitutive model coupling with the strain hardening exponent and strain rate sensitivity exponent in the deformation was put forward and applied to predict the deformation behavior of Ti-46.5Al–2Nb–2Cr.