Feed pump in the circuit Researchers Give Turbine Blades a Second Life

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After around 5,000 flight hours, turbine blades in aircraft engines have to be replaced due to the stresses they have been subjected to—at least up to now ...

After aircraft turbines have operated for several years at temperatures above 1,000 °C 
(1,832 °F) and under extreme mechanical loads, their microstructure has changed to their detriment, and pores form in the material that act as local defects. First-stage turbine blades are therefore usually replaced after around 5,000 flight missions—about three to six years of service. A team at Ruhr University Bochum is now investigating whether the blades might be rejuvenated and used again. This would save energy and raw materials—especially critical materials. The process is being developed by researchers led by Prof. Dr. Sebastian Weber and Dr. Louis Becker from the Chair of Materials Engineering in the joint project “Second_Life”. In addition to the consortium coordinator at Ruhr University Bochum (RUB), the Institute of Materials Research at the German Aerospace Center (DLR) in Cologne is involved, as are the industrial partners Lufthansa Technik, Aalberts Surface Technologies, and Otto Fuchs. The project has been funded since August 2026 for three years under the aviation research program “LuFo Klima VII-1” of the Federal Ministry for Economic Affairs and Energy (BMWE).

The “HIP” diet rejuvenates run-down aircraft turbines

First-stage turbine blades are manufactured from single-crystal nickel-based superalloys because of the high loads they are exposed to. Inside them, the atoms are arranged in a continuous crystal lattice, so there are no grain boundaries that can be weak points at high temperatures. Nevertheless, they become damaged over time. “During turbine operation at high temperature, the blades are subjected to tensile stress due to rotation-induced centrifugal forces and are damaged by what is known as creep fatigue,” Weber explains. The microstructural damage limits their service life. The team therefore wants to put the components through a rejuvenation treatment. “We want to restore the microstructure and the mechanical properties by means of hot isostatic pressing (HIP),” explains research group leader Becker. In this process, the turbines are heated under a certain isostatic gas pressure and then rapidly cooled again. In this way, damage such as creep pores is intended to heal, while the single-crystal nature is preserved at the same time. The aim is to restore the as-new condition so that, after renewed coating with a thermally insulating protective layer, the blades are ready for use again.

An important building block for more sustainable aviation

At the German Aerospace Center, defined creep-fatigue damage is first produced under high-temperature conditions close to those in operation. Then, at the Chair of Materials Engineering at Ruhr University Bochum, suitable HIP process parameters are developed and the changes in the microstructure are investigated, as can be learned further. The researchers then want to mechanically test successfully treated samples again in order to demonstrate whether, in addition to the microstructure, the mechanical performance can also be restored. “By extending the service life of turbine blades, we can reduce both the need for newly manufactured components and the associated use of energy and raw materials,” Weber comments in conclusion.