Research progress on Ti₂AlNb-based alloys and composites for aerospace applications

Ti₂AlNb-based alloys have attracted extensive interest for aerospace applications as they exhibit high specific strength, reasonable room-temperature ductility, acceptable fracture toughness, and excellent creep resistance. However, insufficient high-temperature strength and poor oxidation resistance narrow the service temperature range, as well as forming/reheat cracks during the fabrication process impede their engineering applications. The current paper reviews the design of Ti₂AlNb-based alloys, including Al/Nb ratios, single/multiple elements, and the contribution of first-principles calculations. At the same time, Ti₂AlNb matrix composites are discussed that reinforced by ceramic particles, ceramic fibers/whiskers, carbon nanomaterials, and so on, which improve the properties accordingly. This review highlights the effects and contributions of alloying elements and reinforcements on the phase transformation, microstructural evolution, and properties of Ti₂AlNb-based alloys, with the aim of better understanding the relationships of composition-microstructure-property. The insights gained from this overview can pave the way to design and develop lightweight Ti₂AlNb-based alloys for aerospace applications.