Microstructural design for thermal creep and radiation damage resistance of titanium aluminide alloys for high-temperature nuclear structural applications

• The microstructural effects on thermal creep and irradiation strength are compared.
• The best microstructure for thermal creep and irradiation strength is proposed.
• The thermal processing route to obtain the optimal microstructure is discussed.

Microstructure plays an important role in strengthening of metallic materials. Various microstructures can be developed in titanium aluminide (TiAl) alloys, which can enable different combinations of properties for various extreme environments in advanced nuclear systems. In the present paper the mechanisms for microstructural strengthening and the effects of various microstructural features on thermal creep and radiation damage resistance of TiAl alloys are reviewed and compared. On the basis of the results, the evidence-based optimum microstructure for the best combination of thermal creep and radiation damage resistance of TiAl alloys is proposed. The heat treatment processes for manufacturing the optimal microstructure are also discussed.