Niobium hafnium alloy is a niobium alloy which is formed by adding a certain amount of hafnium and other elements. In the two phase diagram, niobium and beta -Hf form substitutional solid solutions.

Hafnium is a kind of active element, which can be used to produce HfO2 and HfC compounds with oxygen and carbonation in niobium, and can play a role of dispersion strengthening, at the same time, it can reduce the harmful effects of interstitial elements and improve the weldability and coating properties of niobium alloy. Niobium hafnium alloy is one of the most widely used niobium alloys in aerospace engineering and technology.

In 1965, the United States successfully developed Nb-10Hf-1Ti alloy, and it was used for the Appollo manned lunar module under the rocket engine nozzle extension in 1969. In 1975, China successfully developed NbHf10Ti1Zr0.7 niobium alloy.

Niobium hafnium alloys can be divided into two types according to the strengthening methods: solid solution strengthening alloy and solid solution strengthening and dispersion strengthening alloy. Niobium hafnium alloy has good mechanical properties and weldability.

Preparation method：Ingot preparation and plastic processing: Niobium hafnium alloys are usually prepared by electron beam melting and vacuum consumable arc melting, and then extruded or forged at the temperature of 1200 degrees or above, it is rolled and drawn below 500 degrees, which can be made into plates, belts, rods, wires and forgings and other products.

Welding: Niobium hafnium alloy has good weldability. It is usually used to realize the connection of the parent metal by the method of tungsten electrode argon arc welding and electron beam welding. The two kinds of welding methods can also be used to weld the niobium hafnium alloy with titanium and titanium alloy. The quality of the weld is related to the purity of argon and the degree of vacuum, the higher the purity of argon, the lower the residual atmospheric pressure, the better the quality of the weld.

Heat treatment: Generally use the vacuum or inert gas protection annealing treatment and solution aging treatment.

Coating；Cr-Ti-Si and Cr-Fe-Si are usually used as antioxidant coating. The oxidation resistance life of niobium and hafnium alloys coated with these two kinds of coatings was over 150h in air at 1371 degrees.

Purpose；The utility model is mainly used for the extension section of the radiation cooling nozzle of a liquid rocket engine, the body of the thrust chamber, the molten sodium of the space power generation system, the sodium potassium alloy pressure pipe and the turbine pump, the high temperature structural parts of the jet engine, etc..