Constitutive Modeling and Processing Map of Ti–5Al–5Mo–5V–3Cr–1Zr Alloy During Hot Deformation

To investigate the hot deformation behavior of Ti–5Al–5Mo–5V–3Cr–1Zr (Ti55531) alloy, a series of compression tests were performed within the temperature range of 1033–1153 K at constant strain rates 0.001–1 s−1 on a Gleeble-3500 isothermal simulator. The results show that the flow stress decreases with an increase in temperature and a decrease in strain rate. At high strain rate, the flow curves are characterized by obvious discontinuous yielding, followed by slight strain hardening before flow softening and/or steady-state flow. The magnitude of the discontinuous yield drop increases with an increase in temperature. The flow behaviors were described by the Arrhenius equation in α + β phase region and in β phase region respectively. The processing maps considering strains of 0.05, 0.4, 0.6, and 0.9 were drawn. In combination with microstructural observations, it is found that this alloy represents typical instability of flow localization and flow rotation in an unstable flow region. The optimum conditions for hot deformation were found at 0.001–0.1 s−1 and 1003–1153 K.