Deformation kinetics of the Ti-6Al-4V alloy at low temperatures

Abstract

The deformation kinetics of theα + β titanium alloy Ti-6 A1-4V were investigated over the temperature range of 4.2 to 760 K. It was found that the Gibbs free energy of activation AG at 0 K and zero effective stress is ∼ 1.3 eV (∼ 1.25 × 105 J/mole) (∼0.17 μob3), the maximum force for the dislocation-obstacle interaction is ∼ 80 × 10-6 dyne (∼ 80 × 10-11N) (∼ 0.19 μob2) and the activation distance x0 * at which the force first rises rapidly ∼ 1.5b. These quantities, and others, are the same as those for unalloyed titanium, where it was established that interstitial solutes are the obstacles controlling the dislocation motion. The results for the Ti-6A1-4V alloy are in slightly better accord with ρG being independent of temperature than proportional to the shear modulus, but the evidence is not conclusive.