High Temperature Flow Behavior and Processing Map for Air-Cooled Titanium Alloy TC11

The isothermal compression tests for air-cooled titanium alloy TC11 were carried out in the temperature range of 750 similar to 1100 degrees C and strain rate range of 0.001 similar to 10.0 s(-1), and the high temperature flow behavior, the flow instability and the deformation mechanism were investigated in alpha + beta phase field and beta phase field for this alloy by using flow stress-strain curve and processing map. The results show that in excess of peak stress the flow stress decreases continuously with increasing of strain at low temperatures in alpha + beta phase, but first decreases and then reaches an approximately constant value at moderate and high temperatures in alpha + beta phase; the flow stress decreases slightly and then tends gradually toward a constant value with increasing of stain in beta phase field. In the processing maps of this alloy, the domains with high value of eta in alpha + beta phase are about (750 similar to 900 degrees C, 0.001 similar to 0.006 s(-1)) and (900 similar to 1000 degrees C, 0.001 similar to 0.02 s(-1)). In these two domains, the spheroidization of alpha lamellae occurs, and the combination of spheroidization of alpha lamellae and alpha + beta -> beta phase transformation happens, respectively. The domain with high value of eta in beta phase field is about (1000 similar to 1100 degrees C, 0.003 similar to 0.3 s(-1)), where dynamic recrystallization undergoes. The above domains are desirably to be selected for hot working. The domains of flow instability are (750 similar to 875 degrees C, 0.006 similar to 10.0 s(-1)), (875 similar to 975 degrees C, 0.03 similar to 10.0 s(-1)) and (975 similar to 1100 degrees C, 1.0 similar to 10.0 s(-1)), and the manifestations of flow instability are macroscopic shear, adiabatic shear band and non-uniform deformation of beta grains.