Development of gamma titanium aluminide (γ-TiAl) alloys: A review

Gamma titanium aluminides (gamma-TiAl) have been known for decades to be suitable for use in aerospace applications due to their high strength and low density at high temperatures. However, in addition to these good properties, low ductility and low fracture toughness at low temperatures limit the use of the alloy. For this reason, gamma-TiAl alloy development is of great importance, and the aim is to reduce brittleness at room temperature and increase ductility and creep strength at high temperatures. In this study, the effect of additional alloying elements on the gamma-TiAl alloy system was given and discussed for improving the shortcomings of this alloy. Cr, Mo, Nb, B, C, and Si were selected as alloying elements, and the effects of these elements on microstructure and mechanical properties were discussed in the context of alloy design. Various improvements in the properties of these materials have been achieved as a direct result of a better understanding of the phase transformations and microstructural evolution in the system that occur by alloying. In conclusion, it should be notted that additional elements used during the development of an alloy can affect each other for final properties. An element that improves a feature may restrict another feature, or the elements used may not work in harmony with other alloying elements.(c) 2022 Elsevier B.V. All rights reserved.