Superalloy

As superalloys are materials of complex composition (iron, nickel, platinum, chromium, or cobalt - base with the addition of the elements Co, Ni, Fe, Cr, Mo, ​​W, Re, Ru, Ta ​​, Nb, Al, Ti, Mn, Zr, C and B ) means for high temperature applications. They are mostly scale- and high-temperature resistant. They may be produced both by melting and powder metallurgy.

The name superalloy points to materials whose operating temperatures are higher than those of steels, as they have in this temperature range on increased strength. Polycrystalline superalloys reach operating temperatures of about 80 %, single-crystal alloys about 90 % of the melting point. Nowadays mainly nickel -based super alloys. Their temperature resistance is achieved through a mixture of incoherent dispersion hardening, coherent precipitation and solid solution strengthening.

Common brand names are eg Stellite, Tribaloy, Hastelloy, Incoloy, Inconel, NIMONIC, R88DT, Waspaloy or X - 40th

Application

Super alloys are used because of their high price (about 45 € / kg by mid-February 2012) primarily used in engines, turbines and jet engines, power engineering, as well as in aerospace.

In gas turbines are polycrystalline (discs), directionally solidified and single crystal ( blades ) used components. The aim of the development of alloys are as high as possible endured turbine inlet temperatures, and in the second place, a light weight, in order to increase the efficiency.

Example: Inconel alloy 718

Material number: 2.4668, short name: NiCr19NbMo, density: 8.19 g / cm ³.

Chemical composition: 0.04 % C - 19% Cr - 3.0% Mo - 52.5 % Ni - 0.9 % Al - Cu ≤ 0.1 % - 5.1% Nb - 0.9 % Ti - 19% Fe.

This enhanced with Ni3 [ Nb, V] precipitates superalloy makes today 60-70 % of the volume of all nickel-based alloys.