High temperature plastic flow of polysynthetic twinned TiAl single crystal

Abstract

Polysynthetic twinned (PST) TiAl single crystal possesses great potentials for high-temperature applications. The research on high temperature mechanical behavior and wrought process of PST TiAl single crystal have great significance for application in aeroengine blades. In this paper, PST TiAl single crystal was compressed at high temperature to study the dynamic plastic flow behavior. The strength decreased with the increase of temperature and the decrease of strain rate. The processing map of PST TiAl single crystal was calculated using dynamic material model. It is revealed that the wrought temperature of PST TiAl single crystal should be high, whereas the strain rate should be low. The hot deformation activation energy of PST TiAl single crystal was then kinetically calculated to analyse the constitutive equation, which has been verified to be reliable. These paraments and models can guide the selection of hot wrought process and the prediction of high temperature service performance for PST TiAl single crystal, thus providing database to the application of PST TiAl single crystal for designing mechanical systems.