Identification of favorable hot working condition for Ti-6 Al-4V

The hot working performance of Ti-6Al-4V alloy is sensitive to its process parameters and initial microstructure. It has a very narrow range of process parameters. Therefore, to identify favorable hot working conditions, hot compression tests in the temperature range of 700–1000°C and strain rate range of 0.1–100 s⁻¹ were conducted on Gleeble 3500 thermo-mechanical simulator. The experimental results show that deformation temperature and strain rate have significant effect on the flow stresses. Flow stress increases with increase in strain rate and decrease in deformation temperature. The stress-strain curves, generated by compression test, show three types of behavior: flow hardening, flow softening and steady state flow. The activation energy for deformation was determined to be 484 kJ/mol which is much higher than that for self-diffusion in α-Ti and β-Ti (150 kJ/mol). Using Dynamic Materials Modelling (DMM) principle, the favorable condition for hot working of Ti-6Al-4V alloy has been established. Furthermore, optimum condition among favorable conditions has also been established. The same has been validated with the help of microstructural analysis.