Abstract
Compressive strength of β-Titanium alloy (Ti-15V-3Cr-3Sn-3Al) aged at 723K for 6 hours, as (α+β) two-phase alloy, was clarified in a wide range of temperature from 77K to 673K and at strain rates from 10-4 to 103S-1. Thermally activated strain rate analysis (TASRA) was applied to characterize the deformation mechanism. Adiabatic heating and strain rate change effect were taken into account to predict the stress-strain relation at high strain rate, and the experimental results were well convincing. The strain rate sensitivity of stress under constant mobile dislocation density predicts the temperature and strain rate dependences of flow stress in the high strain rate range, while the deformation behaviour in the relatively low strain rate range is understood with due regard to the change of mobile dislocation density. It is found that a single thermally activated process corresponding to α or β phase predominates the deformation behaviour at low and high temperatures, respectively, and may characterize the two-phase alloy as a whole.
