Abstract
In this paper, the mechanical behaviour and microstructure evolution of TC4 titanium alloy during high temperature plastic deformation are studied. The compression experiment was carried out on the Gleeble-3800 thermal simulator at the deformation temperature ranging from 900℃~1100℃ and at the strain rate of 0.1/s~10/s. The experimental results show that the flow softening mechanism of TC4 titanium alloy is dynamic recrystallization under condition of high temperature deformation. As the deformation temperature increases, the volume fraction and size of the β-transformed tissue become larger, and more acicular martensite appears in the β-transformed tissue. With the increase of strain rate, the grain size is reduced. Moreover, under the condition of high-temperature deformation, TC4 titanium alloy has obvious discontinuous yield phenomenon, and the higher the deformation temperature is, the more obvious the discontinuous yield phenomenon is. At low strain rate, TC4 titanium alloy has a slight strain hardening in a small strain rage, then it exhibits the characteristic of continuous softening flow, and it eventually tends to steady state. At high strain rates, TC4 titanium alloy exhibits wave yielding phenomenon.