Powders of the multiphase super alpha2-Ti3AI alloy are processed in a vibrating frame ball mill, in native atmosphere. The structure of the powder particles is investigated by Transmission Electron Microscopy as a function of the duration of the ball milling process. The phenomena associated with this process include an order-disorder transformation and a gradual amorphisation of the a2-Ti 3 Al phase, that later re-crystalIises into new structures, the first belonging to the rhombohedral system. with lattice parameters close to those of alpha-alumina and the second belonging to the cubic system with an fcc unit cell that is very rich in Ti. Th is is explained by a mechanism of oxygen incorporation driven by the continuous deformation of the powder particles, that resembles to high temperature-oxidation of Ti3AI aluminides. The new phases continue to deform by mechanical twinning, forming (0001 ) and (ITI) twins that exhibit a defected character.