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Due to limitations in operating temperature and high-temperature mechanical properties, C-103 alloy and niobium silicide anti-oxidation coatings have been unable to meet the evolving needs of spacecraft. To this end, our country has developed Nb521 (Nb-5W-2Mo-1Zr) niobium alloy based on the Soviet 5ΒΜЦ niobium alloy. The alloy uses a high-temperature anti-oxidation protective coating of molybdenum silicide, which increases the operating temperature to about 1550℃, significantly reducing the flow of propellant used to cool the combustion chamber, thereby effectively increasing the specific impulse of the engine.

Nb521 niobium alloy adds W, Mo, Zr alloying elements and a small amount of C element to the niobium matrix. It further improves the room temperature and high temperature mechanical properties of the niobium alloy through a combination of solid solution strengthening and precipitation strengthening. It is a medium-grade niobium alloy. Strength plastic niobium alloy.

Nb521 niobium alloy has good room temperature formability. Plate spinning can usually be used to prepare uniform transition nozzle extensions. However, most nozzles are obtained by machining from rods. The machining is difficult and the material utilization rate is low. relatively low. Therefore, studying the near-net shape and additive manufacturing of Nb521 niobium alloy is an effective method to improve the utilization rate of this alloy material.

In addition, the molybdenum silicide high-temperature anti-oxidation coating prepared from Nb521 alloy material has a certain self-healing ability, and its linear expansion coefficient is relatively close to that of Nb521 alloy material. Therefore, it has good anti-oxidation protection performance and bonding performance.