Thermally activated process of dislocation glide in Ti–17V and Ti–22V alloys

In order to elucidate the influence of the athermal omega phase (ω ath ) and solute V on the thermally activated process of dislocation glide in β-titanium alloys of Ti–17V and Ti–22V, the values of effective shear stress, activation volume and activation enthalpy were obtained by tensile tests and strain-rate jump tests at various temperatures. Effective shear stresses showed a strong temperature dependence, indicating that yielding is controlled by a thermally activated process of dislocation glide. The temperature dependence of the activation enthalpy suggested that the process of overcoming the Peierls potential controls the dislocation glide below T trans , while interaction with ω ath or solute V is possibly dominant above T trans . It was found that the shearing of ω ath or the interaction with its coherent stress fields are unlikely to be dominant for the thermally activated process of dislocation glide, because the CRSS for the shearing of ω ath is much smaller than the experimental value and the activation volumes estimated for the coherent stress fields are significantly larger than those obtained experimentally. Interaction with a single solute V atom is also unlikely to be dominant because the estimated activation volumes are significantly smaller than the experimentally evaluated values. The interaction between dislocation and several solute V atoms is expected to be reasonable for the thermally activated process for dislocation glide above T trans .