Ti2 AlNb alloys can operate for extended periods at temperatures between 650 and 750 ℃, offering high specific strength, excellent room-temperature fracture toughness, and good creep resistance. These properties make Ti2 AlNb alloys one of the most promising lightweight metallic materials for high-temperature applications. The alloy sheets, with a final thickness of 1 mm, were produced via a clad rolling process, employing a nominal composition of Ti-22Al-24Nb-0.5Mo (at.%) as the rolling material. After the rolled sheets were subjected to solution aging treatment, a significant amount of O-phase precipitated. As the aging temperature increases, the O-phase lamellae grow coarser, and the amount of precipitated O-phase initially increases but then decreases. At 930 ℃, the volume fraction of the precipitated O-phase reaches its maximum value of 52%. Under this heat treatment regime, the nucleation mechanisms for O-phase precipitation include both interfacial instability nucleation and induced nucleation. However, near grain boundaries, the O-phase tends to nucleate and precipitate predominantly through induced nucleation, with fewer O-phase particles forming through interfacial instability nucleation. Following solution treatment at 1 000 ℃ and aging at 815 ℃, as well as solution treatment at 920 ℃ and aging at 800 ℃, the resulting microstructures are bimodal. The solution aging process after rolling has little effect on the precipitation of O-phase variants.