Study on the stress-induced γ → α₂ transformation in a hot-deformed Ti-45Al-10Nb alloy by high-resolution transmission electron microscopy

A stress-induced γ → α₂ transformation phenomenon in a hot-deformed Ti-45Al-10Nb alloy was investigated by high-resolution transmission electron microscopy (HREM). This deformation-induced γ → α₂ phase transformation is an interface related process. The interfacial superdislocations emitted from the deviating semi-coherent α₂/γ interface react with each other or with the moving dislocations in the γ-phase resulting in the formation of the stress-induced α₂-phase. Meanwhile, the orientation of the γ-phase, of which interface the interfacial superdislocation swept, was also changed. The structure of the dislocation ledges plays an important role in the formation of the deformation-induced α₂-phase.