Hot deformation behavior and process parameter optimization of Ti22Al25Nb using processing map

Abstract

The hot deformation behavior of Ti22Al25Nb was investigated by hot compression test. The flow stress–strain curves can be divided into two types: conventional dynamic recrystallization (DRX) and discontinuous DRX. The different softening mechanism and microstructure observation of conventional DRX and discontinuous DRX were analyzed. The processing map (PM) of Ti22Al25Nb was built to predict the safe deformation region. The optimal low strain rate domain (DOM I) with high power dissipation efficiency indicates the complete DRX. Additionally, in the high strain rate and low-temperature domain (DOM III), the power dissipation efficiency is low and some adiabatic shear bands and glide bands are observed, which are unsafe and should be avoided. Finally, the DRX map was established. In DOM I, it reveals low dislocation density and high DRX content, which is in agreement with PM.