Effect of Solution Treatment Temperature on Microstructural Evolution of Ti₂AlNb-based Alloy

  Intermetallic alloys based on an ordered orthorhombic Ti₂AlNb phase are considered as promising materials for aerospace applications. The mechanical properties of the Ti₂AlNb-based intermetallic alloy with three phases of O, B2 and a₂, are sensitive with the phases and microstructure. In the present work, phase transformation of Ti₂AlNb-based alloy during solution treatment at elevated temperatures was investigated by using optical microstructure (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results indicated that the transformation from O to B2 phase occurred and the α₂ phase gradually vanishes with increasing the solution treatment temperature. The solution treatment temperature determine the amounts of O, B2 and α₂ phase and their final microstructural morphologies, and also determine the properties of the material.