Non-isothermal phase transformation kinetics of ω phase in TB-13 titanium alloys

The ω phase transformation kinetics of TB-13 titanium alloy has been analyzed by non-isothermal dilatometry. The average value of local activation energy determined is about 91.7 kJ/mol. The nucleation and growth mechanism of the ω phase has been investigated by the non-isothermal local Avrami exponent. Both the local Avrami exponent and the local activation energy during the ω phase transformation process change significantly with the transformed volume fraction, indicating that the ω phase transformation mechanism in this alloy varies at different stages. The local Avrami exponent lies between 1 and 2 in a wide transformed volume fraction range of 0.17–0.95, indicating that the dominating mechanism of ω phase transformation in TB-13 titanium alloy is the three-dimensional growth with a near-zero nucleation rate.