Applications of high-temperature nickel-based alloys
Nickel-based high-temperature alloys occupy a special and important position in the entire field of high-temperature alloys, which are widely used in the manufacture of aviation jet engines, various industrial gas turbines, the hottest end of the components. If 150MPA-100H lasting strength as the standard, and the current nickel alloy can withstand the highest temperature 〉 1100 ℃, while the nickel alloy is about 950 ℃, iron-based alloys < 850 ℃, that is, nickel-based alloys correspondingly higher than 150 ℃ to about 250 ℃. So people call nickel alloy for the heart of the engine. At present, in the advanced engine, nickel alloy has accounted for half of the total weight, not only the turbine blades and combustion chamber, but also the turbine disc and even after several stages of the compressor blades also began to use nickel alloy. Compared with iron alloys, nickel alloys have the following advantages: higher working temperature, stable organization, less harmful phases and the ability to engage in oxidation and corrosion. Compared with cobalt alloys, nickel alloys can work at higher temperatures and stresses, especially in the case of dynamic blades.
The above advantages of nickel alloys are related to some of their excellent properties.
Nickel is face-centered cubic, very stable and does not undergo isotropic transformation from room temperature to high temperature; this is important for the selection of the base material. Austenitic organization is known to have a number of advantages over ferritic organization.
Nickel has high chemical stability, almost no oxidation below 500 degrees Celsius, and is not subject to the action of warm gas, water and certain salts in aqueous solution at school temperature. Nickel dissolves very slowly in sulfuric acid and hydrochloric acid, and very quickly in nitric acid.
Nickel has a great alloying ability, even the addition of more than ten alloying elements do not appear harmful phase, which provides the potential for improving the various properties of nickel.
Although the mechanical properties of pure nickel are not strong, but the plasticity is excellent, especially at low temperatures plasticity does not change much.
The above advantages of nickel alloys are related to some of their excellent properties.
Nickel is face-centered cubic, very stable and does not undergo isotropic transformation from room temperature to high temperature; this is important for the selection of the base material. Austenitic organization is known to have a number of advantages over ferritic organization.
Nickel has high chemical stability, almost no oxidation below 500 degrees Celsius, and is not subject to the action of warm gas, water and certain salts in aqueous solution at school temperature. Nickel dissolves very slowly in sulfuric acid and hydrochloric acid, and very quickly in nitric acid.
Nickel has a great alloying ability, even the addition of more than ten alloying elements do not appear harmful phase, which provides the potential for improving the various properties of nickel.
Although the mechanical properties of pure nickel are not strong, but the plasticity is excellent, especially at low temperatures plasticity does not change much.