Investigation of residual stresses in new materials for the development of aircraft turbines
Materials and components • Stress scanning • Neutron diffraction
Nickel-based superalloys are particularly suited for use in turbine components, given their unique combination of high temperature strength and high fatigue strength. Their production, however requires water-quenching directly after forging, leading to much higher residual stresses than under standard air cooling. This can result in distortion of the work piece during the machining of the disc into its final shape.
Neutron diffraction techniques have been used to examine the residual stress distributions in a water quenched IN 718 compressor disc. With the results obtained, engineers were able to improve and validate the simulation models they use to predict residual stresses in their work pieces.
Optimised simulation models allow subsequent treatments – such as turning to final shape – to be fine-tuned, thus minimising unwanted distortion and deformation effects.