In-situ and ex-situ testing under pressurized hydrogen using an internal pressure testing system

• Subject Area: Materials Engineering
• Term: Funded in 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563787530

The use of renewable energy will become increasingly important. Hydrogen can play a central role as a climate-neutral energy source. But the effects of hydrogen on the mechanical properties of materials have been poorly investigated so far, as there are no standards or guidelines for uniform testing methodologies. This refers to existing materials in pipelines or fittings and to materials, which still have to be investigated for the use in tank or filling systems. In existing infrastructures primarily steels are used, but light weight materials as aluminum, composites or additively manufactured structures are also used. Hydrogen embrittlement poses a risk as it leads to degradation of the mechanical properties. This happens through interstitial solution of atomic hydrogen, which can diffuse freely through the lattice. Furthermore, there is trapped hydrogen in so-called traps, energetically favorable areas, in which hydrogen can be bound and is then no longer diffusible. The behavior of hydrogen in metallic components is therefore strongly dependent on the microstructure present. According to this, new measurement and testing methods are required for materials science and materials engineering in order to understand the influence of hydrogen holistically. The internal pressure testing system is a chamber system that can be filled with hydrogen under pressure and elevated temperature. In order to create analogies to existing research work and already available data, the testing of hollow specimens is also planned. To extend the range of applications, the self-sufficient use for ex-situ pressurized gaseous hydrogen charging and mechanical loading under a pressurized hydrogen atmosphere in static, quasi-static and dynamic form will also be made possible. Cyclic loading under pressurized hydro-gen conditions with different testing temperatures allows process- and structure-related dam-age evolution under the influence of hydrogen to be characterized and the service life to be quantified. Tests in the LCF- and HCF-regime provide insights into deformation behavior and damage mechanisms as a function of loading level, material and microstructure present, so that a comprehensive understanding of hydrogen fatigue is generated. The internal pressure testing system will strengthen the applicant's competences in the field of fatigue characterization under application-relevant environmental conditions. By integrating other working groups with varying research focuses, other users can also benefit from the diverse application of the major research instrumentation. This ensures a holistic use of the system.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Innendruckprüfsystem zur in-situ und ex-situ Prüfung unter Druckwasserstoffatmosphäre
• Instrumentation Group: 2910 Dynamische Prüfmaschinen und -anlagen, Pulser
• Applicant Institution: Technische Universität Dortmund
• Leader: Professor Dr.-Ing. Frank Walther