G. A. Sargent, University of Dayton, Dayton, OH; D. Li, RMI Titanium Company, Niles, OH; S. L. Semiatin, Air Force Research Laboratory, Wright-Patterson AFB, OH
Ultrafine microstructure Ti-6Al-4V material was obtained in both sheet and billet form via severe plastic deformation processes. Static coarsening of the microstructure of both materials was measured at temperatures of 775 and 815oC for annealing times up to 96 hours. Hot compression and hot tension tests were conducted to establish the dynamic coarsening and its impact on the plastic flow response also at temperatures of 775 and 815oC at strain rates of 10-3 -10-4. The influence of particle size, diffusivity, alpha/beta interface energy, and phase equilibria on static and dynamic coarsening was established. The static and dynamic coarsening kinetics were interpreted in terms of models previously determined for the coarsening behavior at higher temperatures (900, 955oC). The flow-hardening behavior at 775 and 815oC was discussed in relationship to the dynamic-coarsening rates. Detailed microstuctural characterization enabled the determination of the effect of particle size, shape, and stability on plastic flow at temperatures between 775 and 995oC.
Summary: Ultrafine microstructure Ti-6Al-4V material was obtained in both sheet and billet form via severe plastic deformation processes. Static coarsening of the microstructure of both materials was measured at temperatures of 775 and 815oC for annealing times up to 96 hours. Hot compression and hot tension tests were conducted to establish the dynamic coarsening and its impact on the plastic flow response also at temperatures of 775 and 815oC at strain rates of 10-3 -10-4. The influence of particle size, diffusivity, alpha/beta interface energy, and phase equilibria on static and dynamic coarsening was established. The static and dynamic coarsening kinetics were interpreted in terms of models previously determined for the coarsening behavior at higher temperatures (900, 955oC). The flow-hardening behavior at 775 and 815oC was discussed in relationship to the dynamic-coarsening rates. Detailed microstuctural characterization enabled the determination of the effect of particle size, shape, and stability on plastic flow at temperatures between 775 and 995oC.
