THE KINETICS OF PHASE TRANSFORMATIONS DURING CONTINUOUS COOLING OF THE Ti6A14V ALLOY FROM THE SINGLE-PHASE β RANGE

The paper reports on a study of the kinetics of phase transformations during continuous cooling of the alpha-beta Ti6A14V titanium alloy from the beta range. After cooling from 1020 degrees C at a rate higher than critical the martensitic beta -> alpha transformation occurred. At rates lower than critical in addition to the martensitic reaction also the diffusional beta -> alpha transformation took place. Metallographic examination of samples cooled at various rates within the range of diffusional transformations, revealed variations in the a phase morphology changing from lamellar, after cooling at between 7.3 and 0.015 degrees C/s, to granular, as observed after cooling at 0.012 degrees C/s. The phase transformations were also clearly seen in dilatometric curves.