What is nickel-based superalloy?
Nickel-Based Superalloy Definition:
Nickel-based superalloy is a class of special alloys with nickel as the main component and the addition of chromium, cobalt, molybdenum, titanium, aluminium and other elements. These alloys are widely used in extreme environments, especially in aerospace and gas turbine engines, due to their ability to maintain excellent mechanical properties, oxidation resistance and corrosion resistance at high temperatures.
Characteristics of nickel-based high temperature alloys:
Excellent high-temperature strength: nickel-based high-temperature alloys still have high strength in high-temperature environments from 600°C to 1000°C, which is one of the materials with the highest high-temperature strength of currently known alloys.
Good oxidation and corrosion resistance: nickel-based high-temperature alloys show excellent stability in high-temperature oxidation and corrosion environments, and are able to resist the erosion of materials by high-temperature gases, molten metals, molten salts and so on.
Creep resistance: when loaded for a long time at high temperatures, nickel-based high-temperature alloys can effectively resist creep deformation and maintain their structural integrity.
Thermal stability: the microstructure of nickel-based high-temperature alloys remains stable at high temperatures, and no significant phase or organisational changes will occur.
Composition of nickel-based high-temperature alloys:
Nickel (Ni): acts as a matrix element to provide high temperature strength and oxidation resistance of the alloy.
Chromium (Cr): improves oxidation and corrosion resistance.
Cobalt (Co): enhances high temperature strength and thermal stability.
Molybdenum (Mo) and tungsten (W): add strength and hardness to alloys.
Titanium (Ti) and aluminium (Al): further increase the high temperature strength and creep resistance of the alloy through the formation of the γ'(Ni3(Al,Ti)) precipitated phase.
Applications of nickel-based high temperature alloys:
Aircraft engines: Nickel-based high-temperature alloys are widely used in the manufacture of turbine blades, turbine discs, combustion chambers and other components, which are required to operate at extreme high temperatures and pressures.
Gas turbine: applied to the hot end parts of industrial gas turbines, such as turbine blades, combustors, nozzles, etc.
Nuclear reactors: Nickel-based alloys are used in the nuclear industry as structural materials in high-temperature corrosive environments.
Chemical equipment: used in the manufacture of high temperature corrosion-resistant equipment and pipelines, especially in strong corrosive media and high temperature gas environment.
Preparation and processing of nickel-based high temperature alloys:
The manufacture of nickel-based high-temperature alloys usually involves complex smelting and heat treatment processes to ensure the stability of their microstructure and properties. Advanced processing techniques, such as single crystal growth and directional solidification, are also used to produce nickel-based high temperature alloy components with higher performance.