The development of nickel and cobalt alloys is closely intertwined with the history of modern aerospace. Many of the alloys used in aerospace belong to the group known as superalloys. These alloys combine extreme temperature resistance with strong anticorrosive properties. Most superalloys contain nickel or cobalt as their main constituent. Stability at high temperatures, high creep strength, good fatigue behavior, slow crack propagation, toughness and resistance to high-temperature oxidation comprise the critical properties and features of this group of materials.
Super alloys are commonly used in gas turbine engines in those areas of the engine that are subject to high temperatures and which require high strength, excellent creep resistance, as well as corrosion and oxidation resistance. In turbine engines this is in the high pressure turbine where blades can face temperatures approaching if not beyond their melting temperature. New jet engines are more efficient because of higher operating temperatures, requiring higher-performing components. The use of super alloys can allow the operating temperature to be increased. Besides increasing efficiency and power output, higher temperatures result in reduced emissions because the combustion cycle is more complete. for example INCONEL 718 used in disc of gas turbine.
Compressor of Gas Turbine
The engine represents the heart of the aircraft. Very stringent requirements apply to their materials, due to the extreme thermal and dynamic loads that are sustained. In medium and high pressure compressor areas, high strength and resistance to high-temperature corrosion are indispensable requirements. Semi-finished products such as rods and bars, discs, plates, blades and forged parts, are used in these applications. for example INCONEL 718 is suitable for rotating and non rotating parts. Also from titanium used in parts of compressors and fans.