Mapping the residual stress distribution on additive repaired turbine blisk aerofoils

Gas turbine aerofoils can be subjected to severe wear and potential for cracking due to harsh operating environment, which involve both high rotational speeds and temperatures.Repairing the damaged aerofoils can save around 45% in carbon footprint and 36% in total energy over replacing with a new aerofoil. Energy and cost saving is much higher for turbine blisks, where the whole blisk needs to be replaced even if a single aerofoil is damaged.Thus, turbine blisk aerofoil repair is of great interest to aerospace industries from the perspective of reducing cost and increasing sustainability. Additive manufacturing (AM) has been used for repairing ‘end of life’ turbine blisk aerofoils. However, during repair, significant residual stresses arise due to large and repeated thermal gradients, which could lead to in-service failures.This precludes the use of the repaired parts in aircraft. Therefore, it is vital to investigate residual stress distribution on the AM-repaired blisk aerofoils.