Nickel-based superalloys: Deformation/casting/new alloy upgrades from generation to generation

Nickel-based superalloys generally work under certain stress conditions above 600℃, which not only has good high-temperature oxidation resistance and corrosion resistance, but also has high high-temperature strength, creep strength and lasting strength, as well as good fatigue resistance. It is mainly used for structural components working under high temperature conditions in the aerospace field, such as working blades, turbine disks, combustion chambers, etc.

Nickel-based superalloy can be divided into variable alloy, cast superalloy and new superalloy according to the manufacturing process. Nickel-based cast superalloy is mainly used in the engine for turbine guide blades, the operating temperature can reach 1100°C or more, and can also be used for turbine blades, whose temperature is lower than the corresponding guide blade 50-100°C.

With the higher and higher working temperature of heat-resistant alloy, the strengthening elements in the alloy are more and more, and the composition is more complex, resulting in some alloys can only be used in the cast state, and can not be deformed by hot processing. Moreover, the increase of alloying elements makes the composition segregation of nickel-based alloys serious after solidification, resulting in uneven microstructure and properties. Using powder metallurgy process to produce superalloy can solve the above problems. Because the powder particles are small, the cooling speed is fast when the powder is made, the segregation is eliminated, the hot processability is improved, the alloy that can only be cast is turned into a deformation superalloy that can be hot processed, the yield strength and fatigue properties are improved, and the powder superalloy has produced a new way for the production of higher strength alloys. Powder superalloy is mainly used in the manufacture of turbine disc of advanced aero engine with high thrust ratio, and also in the production of high temperature hot end parts such as compressor disc, turbine shaft and turbine baffle of advanced aero engine.