Hot Deformation Behavior and Processing Maps of a New Ti-6Al-2Nb-2Zr-0.4B Titanium Alloy

The hot deformation behaviors of a new Ti-6Al-2Nb-2Zr-0.4B titanium alloy in the strain rate range 0.01-10.0 s(-1) and temperature range 850-1060 degrees C were evaluated using hot compressing testing on a Gleeble-3800 simulator at 60% of deformation degree. The flow stress characteristics of the alloy were analyzed according to the true stress-strain curve. The constitutive equation was established to describe the change of deformation temperature and flow stress with strain rate. The thermal deformation activation energy Q was equal to 551.7 kJ/mol. The constitutive equation was epsilon =e(54.41)[sinh (0.01 sigma)](2.35)exp(-551.7/RT). On the basis of the dynamic material model and the instability criterion, the processing maps were established at the strain of 0.5. The experimental results revealed that in the (alpha + beta) region deformation, the power dissipation rate reached 53% in the range of 0.01-0.05 s(-1) and temperature range of 920-980 degrees C, and the deformation mechanism was dynamic recovery. In the beta region deformation, the power dissipation rate reached 48% in the range of 0.01-0.1 s(-1) and temperature range of 1010-1040 degrees C, and the deformation mechanism involved dynamic recovery and dynamic recrystallization.

Automated summary

The hot deformation behaviors of a new Ti-6Al-2Nb-2Zr-0.4B titanium alloy were evaluated and a constitutive equation describing the change of deformation temperature and flow stress with strain rate was established. The study found that the deformation mechanism of the alloy varies under different temperatures and strain rates.