At present, the relatively mature commercial niobium alloys in use are mostly C103(Nb-10Hf-1Ti-0.7Zr) and Nb521(Nb-5W-2Mo-1Zr). The Nb521 niobium-tungsten alloy (Nb-5W-2Mo-1Zr) developed by our country is similar to the 5BMV alloy developed by the Soviet Union. 5BMV alloy was applied in the manufacturing of the thrust chamber body of the binary liquid rocket engine in the Soviet Union. Under the protection of the high-temperature anti-oxidation coating of molybdenum silicide, the working temperature of the thrust chamber could reach about 1550℃, significantly reducing the flow of propellant used to cool the combustion chamber, which was conducive to improving the performance of the engine. With the increasing demand for the development of more types of engines, the application of Nb521 niobium-tungsten alloy in China's aerospace field has become more extensive. It is not only used in binary liquid rocket engines but also in some high-temperature components of other high-speed aircraft. However, alloys such as niobium-tungsten and niobium-hafnium have relatively high densities and cannot meet the urgent weight reduction requirements of the new generation of aircraft. To obtain lower-density alloys, researchers have developed a variety of low-density niobium alloy systems, such as Nb-Ti-Al, Nb-Ti-Al-Cr, Nb-Ti-Al-Mo, Nb-Ti-Al-Cr-W, etc. However, when evaluating whether a material is usable, it is necessary to comprehensively consider the alloy's density, high-temperature strength, and plastic-brittle transition temperature, among other properties. Among them, the plastic-brittle transition temperature is particularly important for low-density niobium alloys, as hypersonic aircraft and aerospace vehicles all need to operate at altitudes of tens of thousands of meters or even in space environments. Its operating temperature range can be from above 1000℃ to minus 100℃ or even lower. Niobium alloys generally have good high-temperature performance. However, in the low-temperature range, niobium alloys often undergo plastic-brittle transformation, with a sharp decline in plasticity and the material showing considerable brittleness.
Lightweight niobium alloy materials for cryogenic environments and their preparation methods and applications belong to the field of alloy preparation technology, aiming to solve the technical problem that existing niobium alloys are difficult to achieve high strength and high toughness in the low-temperature range. The plastic-brittle transition temperature of lightweight niobium alloys has been significantly reduced through multi-alloying of tungsten, molybdenum, rhenium, hafnium, titanium, aluminum, vanadium, chromium, zirconium and other elements and appropriate proportions. The high-temperature strength of niobium alloys has been enhanced through solid solution strengthening. Add low-density elements to reduce the density of the alloy; The lightweight alloy material for cryogenic environments prepared by the present invention still possesses outstanding properties such as high strength, high toughness and excellent plasticity at -196 ℃. Meanwhile, this alloy has a low density and still possesses excellent mechanical properties and superplasticity at a high temperature of 1000℃. This alloy can be widely used in deep space exploration, Antarctic and Arctic exploration and other fields.
