We report results of our detailed studies on the initial oxidation process of TiAl with a 2 eV hyperthermal oxygen molecular beam (HOMB) and thermal O-2 in the backfilling. The oxidation processes are monitored by X-ray photoemission spectroscopy (XPS) measurements in conjunction with synchrotron radiation (SR). Oxidation of both Al and Ti occurs during the oxidation. The incident-energy and surface-temperature dependences of oxidation reveal that the precursor-mediated dissociative adsorption is the dominant initial step of oxidation in the thermal O-2 backfilling. Thus, the efficiency of oxidation is higher for the thermal O-2 backfilling than for the HOMB dose. The result is quite different from that on TiNi where the HOMB dose has the advantages in oxide layer growth at high O coverage. We succeeded in fabricating blue colored TiO2 and Al2O3 containing layers, combining HOMB and surface annealing. (C) 2013 Elsevier B.V. All rights reserved.