Ti2ZrO Phases Formed in the Titanium and Zirconia Interface After Reaction at 15501C

ed with titanium at 15501C/30 min. The interface was charac-terized by analytical transmission microscopy (transmis-sion electron microscopy/energy-dispersive spectroscopy). The lamellar and the spherical Ti2ZrO as well as the orthorhombic b0-Ti were found to exist in the titanium side after cooling down to room temperature. The crystal structures of the lamellar and the spherical Ti2ZrO were orthorhombic and hexagonal, respec-tively. On heating, the dissolution of a large amount of zirco-nium and oxygen into titanium gave rise to the metastably supersaturated disordered a-Ti(Zr, O) solid solution where two different Ti2ZrO phases subsequently precipitated, while the b-Ti coexisting with a-Ti at high temperatures was transformed to the orthorhombic b0-Ti during cooling. The spherical hexag-onal Ti2ZrO was an ordered structure, with Zr and O occupying substitutional and interstitial sites, respectively. The orientation relations between a-Ti and the lamellae orthorhombic Ti2ZrO were determined to be [0001]a-Ti//110Ti2ZrO and (1010)a-Ti//ð110ÞTi2ZrO; meanwhile, those between the a-Ti and the spherical hexagonal Ti2ZrO were [0001]a-Ti//0001Ti2ZrO and (1010)a-Ti//ð1010ÞTi2ZrO. I