Kinetics of static globularization of titanium-6aluminum-4vanadium
Abstract
The evolution of the lamellar-colony microstructure to equiaxed morphology during heat treatment of a hot-worked, two-phase titanium alloy was established. For this purpose, the alpha/beta alloy Ti-6A1-4V was isothermally upset at 900°C (1650°F) and 955°C (1750°C) and subsequently annealed for times ranging from 0.5 to 100 hours. The degree of the breakup of alpha-phase lamellae into lower-aspect-ratio during static annealing was measured and related to the imposed strain estimated using finite element analysis (FEA). The kinetics of the static globularization of the alpha phase was found to depend on the amount of strain and annealing temperature but was not affected by the specific deformation temperature for material tested in the temperature regime between 900 and 955°C. In addition, interrupted deformation with long delay times (1 to 4 hours) did not affect the globularization kinetics to a great degree when compared to single pass deformation. The measurements provided insight into the mechanisms controlling the lamellar-to-globular transformation.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 2000
- Bibcode:
- 2000PhDT.......290S