Flow behavior modeling of a Ti–6Al–7Nb biomedical alloy during manufacturing at elevated temperatures

• Flow stress is substantially sensitive to deformation strain rate and temperature.
• Employing an Arrhenius-type equation for describing high temperature flow behavior.
• Material constants, A and Q in the constitutive equations are functions of strain.
• High reliability of the proposed strain-dependent constitutive equations.

A proper constitutive base model has been developed to predict the high temperature compressive flow behavior of a Ti–6Al–7Nb biomedical alloy in two phase α + β region. The isothermal hot compression tests were carried out in the temperature range of 850–1000 °C under the strain rates of 0.0025, 0.025 and 0.25 s−1 up to the true strain of 0.65. The constitutive model has been developed through a hyperbolic-sine Arrhenius type equation to relate the flow stress, strain rate and temperature. The influence of strain has been also incorporated by considering the variation of material constants as a function of strain. The proposed constitutive equation has been described in terms of Zener–Hollomon parameter in an exponential type equation, the accuracy of which has been evaluated using standard statistical parameters. The predicted flow stress curves are appropriately found to be in good agreement with the experimental ones.