Fraunhofer Institute for Mechanics of Materials IWMHydrogen combustion in aircraft engines produces significantly more water vapor in the exhaust than kerosene. The consequences for the service life of turbine materials have hardly been studied to date. Fraunhofer IWM is developing a novel test rig to test nickel-based alloys in situ for the first time under realistic high-temperature water vapor and hydrogen atmospheres. Ten materials will be tested, damage mechanisms elucidated, and reduction factors determined. This will create an important knowledge base for companies seeking to safely design hydrogen-compatible turbine components.
Sustainable turbine components through extended service life for evolutionary and revolutionary propulsion systems
Ongoing research project
Project description
Market needs and challenges
The aviation industry is turning to hydrogen combustion to reduce CO₂ emissions in the future. This increases the water vapor content in the exhaust gas to about 12%. To date, little research has been conducted on how this affects the fatigue life of nickel-based cast materials in low-pressure turbines. Scattered data in the literature suggest significantly reduced service lives. Without reliable knowledge, turbine components for hydrogen propulsion systems cannot be designed safely and economically.
Project approach
Fraunhofer IWM is developing a novel mini-autoclave test rig that, for the first time, will enable low-cycle fatigue (LCF) tests to be conducted in situ under realistic water vapor and residual hydrogen atmospheres at elevated pressure and high temperature. In-situ and reference tests are being conducted on ten nickel-based alloys and supplemented by metallographic and fractographic analyses to elucidate damage mechanisms.
Contribution to addressing challenges
The test data yield strain-rate-dependent fatigue life curves and reduction factors relative to a standard atmosphere - a robust basis for materials selection and service life prediction for future low-pressure turbines. The test rig that has been set up is also available for further research into hydrogen combustion and positions Fraunhofer IWM as a competent partner for industrial companies in this field of the future.
Fraunhofer IWM’s work packages in the project:
Fraunhofer IWM will first establish a comparative database on nickel-based cast materials in a steam atmosphere through a literature review. The centerpiece of this effort is the development and commissioning of a novel mini-autoclave test rig equipped with specialized strain measurement technology, which will be used to conduct LCF fatigue tests in situ under steam and residual hydrogen atmospheres at high temperatures and overpressure. In addition, metallographic and fractographic analyses are being conducted to elucidate damage mechanisms. The final results will include a ready-to-use, versatile test bench, a comprehensive database of test data, strain-time curves, and reduction factors for life assessment compared to a standard atmosphere - thereby providing concrete, directly applicable results for materials selection in hydrogen-powered turbines.
Based on the project results, Fraunhofer IWM can offer industrial companies the following research and development services:
In-situ LCF testing under steam and hydrogen atmospheres
Fatigue testing of materials under realistic operating conditions at high temperatures and elevated pressures. The data generated is more reliable than that from conventional laboratory air tests.
Materials screening for hydrogen applications
Rapid evaluation of the suitability of existing and new alloys under elevated water vapor content to support materials selection for new generations of engines.
Determination of reduction factors and Wöhler curves
Reliable service life parameters compared to those in a standard atmosphere enable a more realistic and, at the same time, more cost-effective component design.
Consulting on materials and coating qualification under hydrogen exposure
Well-founded assessments based on a unique database reduce development risks and costs for new hydrogen applications.
Use of the autoclave test rig for additional environmental conditions
With the ability to expand to TMF tests, crack propagation measurements, and other gas compositions, flexible testing capabilities are also available for stationary gas turbines, gas engines, and other H2 applications.
