Hot rotors
Metallurgical assembly in jet engine construction

The materials selected for hot compressor and turbine rotor discs must have high mechanical strength properties: burst strength, low-cycle fatigue strength (disc bore) and creep-elongation strength (disc rim), over a temperature range from 450 ˚C for the first disc, up to 700 ˚C for the last high-pressure compressor disc or high-pressure turbine disc.

The alloys chosen by engine manufacturers are exclusively from the nickel superalloy family (table 2), and are processed by hot forging, which enables the development of fine, fatigue-resistant microstructures. These nickel-matrix alloys are both strengthened by solid solution (Co, Cr, Mo, Hf...), for creep resistance, and by structural hardening, via one or more ordered...