Prediction of hot compression flow curves of Ti–6Al–4V alloy in α + β phase region

Prediction of material flow behavior is essential for designing the forming process of any material. In this research, experimental flow curves of Ti–6Al–4 V alloy were obtained using the isothermal hot compression test done at 750–950 °C with 50 °C intervals and constant strain rates of 0.001, 0.005 and 0.01 s−1. For prediction of hot deformation flow curves two methods of modeling were applied. In the first method, an entire flow curve was modeled using Sellars equation. In the second one, modeling of a flow curve up to the peak point was carried out with Cingara model, and modeling beyond that was performed with a model developed based on the Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory. The accuracy of each model was examined through a statistical method. Results showed that flow curve modeling using Cingara model and JMAK theory leads to results that are more consistent with the experimental data.

► Flow curves of Ti–6Al–4 V alloy can be well modeled using Cingara model and Johnson–Mehl–Avrami–Kolmogorov (JMAK) theory.
► Variations of the inconsistency error for Sellars equation are much higher than those obtained for Cingara and JMAK theory.
► Flow curve modeling using hyperbolic sine equation lacks acceptable accuracy for the flow curves with sharp peak point.