High temperature deformation behaviors of Ti-45Al-2Nb-1.5V-1Mo-Y alloy

The high temperature deformation behaviors of Ti-45Al-2Nb-1.5V-1Mo-Y alloy were investigated in the temperature range 1100–1250 °C and the strain rate range 0.001–1.0 s^?1. The true stress-strain curves exhibit typical work hardening and flow softening features; The peak stress of current alloy decreases with increasing temperature and decreasing strain rate, which can be represented by a hyperbolic sine equation using the Zener-Hollomon parameter. Thanks to the additions of element Mo and V, and the resulting B2 phase, this alloy possesses a low activation energy value of 370 kJ/mol, as well as a wide processing window of temperature above 1150 °C and strain rate under 0.1 s^?1. The deformed microstructure consists of dominated DRX areas plus several remnant lamellar colonies; the inhomogeneous deformation microstructure is ascribed to the anisotropic plastic flow of lamellar colonies. By TEM observation and EBSD analysis further, the deformation mechanism of current alloy is concluded as dislocation slip and mechanical twins.