Physically-based constitutive model for flow behavior of a Ti-22Al-25Nb alloy at high strain rates

The objective of the study is to understand the dynamic flow behavior of Ti-22Al-25Nb alloy at high temperatures using a modified Zerilli-Armstrong (Z-A) model. To investigate the dynamic mechanical behavior of titanium alloy, the material was subjected to quasi static and dynamic compression testing. It is found out that the modified Z-A models possess better predictability in evaluating the flow behavior of the Ti-22Al-25Nb alloy at elevated strain rates and temperatures. The model well established the quasi-static and dynamic behavior of the titanium alloy, mainly the effects of strain hardening and thermal softening. The regimes of high strain rate deformation behavior represented by dynamic recrystallization (DRX), lamellar globularization and the instability flow have been discussed. Using transmission electron microscopy (TEM) studies, it is found that the dislocation density is directly associated with strain rate.