Abstract:Based on the analyses of the microstructures and phase diagrams of the TiAl-based alloy, the relationship among the composition, structure and mechanical properties of the B2-containing γ-TiAl alloys was reviewed. The refinement of microstructures and improvement of mechanical properties of TiAl alloy through stabilization of the β/B2 phase were reviewed. The mechanism of the superplastic behavior of the B2-containing γ-TiAl alloys was discussed. With a reasonable addition of β-stabilizer, metastable B2 phase can be maintained, which is favorable for fine-grained structure and better high-temperature deformation behaviors. The mechanical properties of the B2-containing TiAl alloy, including the deformability and elevated temperature properties, can also be improved with doping elements and subsequent hot-working processes. The above mentioned researches discuss a new way for developing TiAl alloys with comprehensive properties, including good deformability and creep resistance.

Key words: β-stabilizing elements; B2 phase; TiAl-based alloys; phase diagram; grain refinement; thermal processing; superplastic deformation