Both scanning transmission electron microscopy (STEM) and atom probe tomography (APT) were exploited to study variations in chemical composition and phases that took place during thermo-mechanical processing and following slow continuous heating of Ti-10V-3Fe-3Al (wt%) alloy. For the first time for the rapid-cooled alloys, athermal �� (��ath)-assisted nucleation of �� phase (���1 nm) was revealed by high resolution STEM. No presence of ��ath was detected after heating to 450 ��C, which was explained by its consumption by intragranular �� and dissolution. While binomial analysis of APT data after thermo-mechanical processing revealed no changes in chemical composition of ��ath compared to that of �� matrix, heating the sample up to 375 ��C resulted in Ti���rich domains depleted in both �� and �� stabilisers. The results suggested the simultaneous occurrence of displacive and diffusional mechanisms for formation and growth of intragranular ��.