Mechanical behavior of Ti–6Al–4V at high and moderate temperatures—Part II: constitutive modeling

A physically-based model for the deformation of Ti–6%–Al-4%V is proposed. The various deformation mechanisms active in this material over the whole range of temperatures of industrial interest are discussed, and a strategy by which the relevant strengthening effects are captured in the model is proposed. The flow stress contains a thermal and an athermal component. The thermally activated processes are modeled based on the Kocks–Mecking formalism, while the athermal processes are simulated using an internal state variable. The deformation of the α-and β-phases is captured separately. The model is calibrated based on experimental results obtained from tests performed in the temperature range (77–1400 K) and at strain rates between 10−3 and 10 s−1. The model predictions are extrapolated to strain rates as high as 2000 s−1. The experimental findings are presented in the companion paper.