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With the rapid development of aerospace technology, the engine system requires the thrust chamber to be lightweight and able to adapt to the aerodynamic heating effect of rarefied flows in adjacent space. The mass of the thrust chamber is mainly concentrated on the extension section. The extension section produced by traditional stainless steel materials is heavier and can only adapt to The high-temperature environment generated by its own work; niobium-tungsten alloy and niobium-hafnium alloy have been widely used in high-performance thrust chamber extensions in recent years. This type of alloy has superior high-temperature properties, but has a larger density. The density of niobium-tungsten alloy and niobium-hafnium alloy About 8.7g/cm3. The thrust chamber body made of niobium-tungsten alloy and niobium-hafnium alloy is relatively heavy and does not meet the purpose of lightweight engine design. It is necessary to develop a new metal material with low density and high medium-temperature strength to achieve the purpose of lightweight design of high-performance engines and to improve the operating temperature and combustion efficiency of the engine.

Many countries have developed a variety of low-density niobium alloys that can be used at 800℃~1300℃, have low density and good oxidation resistance. This type of alloy is mainly formed by adding other alloy elements on the basis of Nb-Ti-Al alloy, such as Nb-39Ti-6Al, Nb-35Ti-6Al-V, Nb-34Ti-6A1-4V-1Zr, Nb-32Ti -7A1-8V-1Zr and Nb-32Ti-7A1-8Cr-1Zr, etc. The tensile strength of this type of alloy at room temperature is ab>800 MPa, and the elongation is 8≥12%. It can work for a long time below 700℃ without anti-oxidation coating. After applying a silicide coating on the surface, it can work for a long time below 1250℃ ( More than 100 hours) work.