Nickel-niobium alloy, including the weight ratio of the following components: Ni30-60 parts; Nb1-3 servings; Ti20-30 copies; Cr5-10 servings; Al5-10 servings; Si10-20 servings; Hf1-3 servings. The nickel-niobium alloy is scientific and reasonable in formulation, and can be widely used in aerospace and nuclear industry. Compared with the prior art, the Ni-Nb alloy improves the oxidation resistance at high temperature by adding Si, Cr, Al, Ti and Hf. The nickel-niobium alloy has simple preparation process and is suitable for industrial production.
Superalloy is an important material for high temperature structural parts in aerospace and nuclear industry. Since the 1950s, the development of superalloys has focused on nickel-based superalloys. The current application of nickel-based single crystal superalloys is limited by its own melting point (about 1400℃), and the upper limit of continuous use temperature is only 1100℃. With the rapid development of industrial construction and science and technology, it is urgent to use metal materials in the temperature range of 1093℃-1370℃. Therefore, it is imperative to develop ultrahigh temperature structural materials to replace nickel-based single crystal superalloy.
Niobium is recognized as a key alloying element in several major nickel-based forged alloys. Niobium belongs to VB refractory metal, melting point 2468℃, bcc structure, its thermal expansion coefficient is 7.2×10-6/℃. The density is similar to steel, the strength can be maintained to 1649.9℃, and can withstand certain mechanical deformation. Niobium is extremely stable in corrosive medium, with small thermal neutron capture cross section, good thermal conductivity, and low plastic-brittle transition temperature (-160℃). Pure metal niobium has high solid solubility for many strengthening elements such as Mo, W, V, Ta, etc.
Because of its superior physical and chemical properties, niobium alloy may be the first choice to replace nickel base single crystal superalloy. However, niobium alloy oxidation resistance is poor, pure metal niobium even at 600℃ pest oxidation phenomenon. Its oxidation belongs to the system with obvious cracks in the oxide layer. With the thickening of the oxide layer, the internal stress generated at the interface between the oxide and the metal will make the oxide layer crack, followed by catastrophic oxidation. Therefore, it is important to improve the high temperature oxidation resistance of niobium and niobium alloys.
