Activation Enthalpy for Yielding in Fully-Lamellar Ti-6Al-4V

This study investigates the mechanical properties of fully-lamellar Ti-6Al-4V, focusing on thermally activated processes behind yielding. Temperature dependences of yield stress, effective stress, activation volume, and activation enthalpy were examined within the temperature range of 77 K to 650 K. The change in the activation volume indicates a change in the deformation mechanism as a thermally activated process. The activation enthalpy in the fully-lamellar Ti-6Al-4V was closer to that of the basal slip in single-crystalline commercially pure Ti, indicating the dominance of basal slip in the fully-lamellar Ti-6Al-4V. Additionally, this study compares the difference in activated slip systems of this alloy with bimodal Ti-6Al-4V and Ti-0.45O, and suggesting changes in deformation mechanisms.