With the continuous improvement of the flight speed of hypersonic vehicles, the demand for lightweight, high-strength, and high-temperature resistant alloy materials in the aerospace field is becoming more and more urgent. The materials currently available are high-temperature titanium alloys, such as TA15 or Ti65, nickel-based superalloys, TiAl and Ti3Al intermetallics, etc. Ti2AlNb alloy is a newly developed lightweight, high-temperature resistant structural material in Ti3Al series intermetallic compounds, which can be used for a long time at 650~750°C and above 1000°C in the short term. Its service temperature is more than 100 °C higher than that of Ti65 and other high-temperature titanium alloys, and its density is much lower than that of high-temperature alloys, and its comprehensive mechanical properties such as room temperature plasticity, high-temperature specific strength, fracture toughness, and creep resistance are far better than those of TiAl and Ti3Al alloys.
The Ti2AlNb alloy, often referred to as an orthogonal (O) phase alloy, was discovered by Banerjee et al. in 1988 and has more slip systems and therefore better ductility. In addition, the O phase exhibits better mechanical properties such as high strength-to-weight ratio, fracture toughness, oxidation resistance, and formability, and heat treatment of the alloy results in five major microstructures, including complete B2 and α2+B2, layered, bimodal layered, equiaxed, and duplex O phase microstructures. Its excellent performance has almost become the best choice of high-temperature structural materials for hypersonic vehicles, and has received extensive attention and in-depth research from scholars at home and abroad.
