The influence of thermomechanical processing on microstructural evolution of Ti600 titanium alloy

The influences of thermomechanical processing on microstructural evolution of Ti600 alloy were studied in the temperature range of 800–1100 °C, and at the strain rate of 0.001–10 s−1. During the isothermal compression experiment, the flow stress–strain curves are examined in the β single-phase and in the α + β two-phase regions. The results show that the thermomechanical processing parameters have significant influences on the microstructure of Ti600 alloy, especially on the grain size, morphologies of α phase. Moreover, the microstructural evolution was analyzed by optical microstructure (OM) and transmission electron microscopy (TEM). It was found that typical of dynamic recovery and dynamic recrystallization phenomenon occurring in the thermomechanical processing. These results will optimize the microstructural control for hot working of Ti600 alloy and deepen the understanding of the flow softening mechanism of near-α titanium alloy.

► Temperature and strain rate have great influence on the microstructure features.
► The formation of sub-grain and dislocation wall is the typically microstructure features observed in the β single-phase.
► The elongated lamellar α platelets kinked increasingly and break up under the α + β processing conditions.
► The softening mechanisms of the Ti600 alloy hot compressed at 1000–1100 °C are mainly dynamic recovery.