The use of hydrogen as an energy carrier depends on safe infrastructures for its storage and transport. Materials and components for pressure vessels and pipelines for gaseous hydrogen must be tested and qualified regarding their susceptibility to hydrogen embrittlement. Currently, many components that come into contact with pressurized hydrogen are designed very conservatively or subjected to very time consuming and costly mechanical fracture and fatigue tests. The qualification of new materials for hydrogen applications can take several years. Materials characterization and qualification is therefore a success factor for the ramp-up of the hydrogen economy.
This is precisely where the HyLife research project comes in, a collaboration between the Fraunhofer Institute for Mechanics of Materials IWM and the National Institute for Standards and Technology (NIST) in the USA, which has just begun and will run until 2028. In its ICON (International Cooperation and Networking) research program, the Fraunhofer-Gesellschaft promotes strategic cooperation between Fraunhofer and an outstanding international research partner.
The overarching goal of HyLife is to develop less conservative, yet reliable design guidelines for components that operate under pressurized hydrogen. To this end, faster and more meaningful qualification concepts for hydrogen infrastructure components are being developed. The advantages are obvious: More materials-efficient design of infrastructures and time and cost-efficient qualification of components support the accelerated development of a sustainable energy sector.
The key to this is a validated physical prediction model for the service life of steel parts with welded seams. The model is intended to reliably predict the damage to materials in contact with hydrogen based on their microstructure and certain physical characteristics. This is set to be a paradigm shift in service life prediction and reduce the need for complex and expensive tests on the formation and propagation of cracks for safety assessments. The result: lower production costs and accelerated innovation cycles.
An innovative micro sample testing technique developed by Fraunhofer IWM is being used to determine fracture toughness and crack growth. The measurement results are compared with unique high-throughput fatigue tests on a macro scale conducted by NIST. The partners also complement each other in microstructure analysis, materials data evaluation, and modeling for the precise measurement of decohesion of mechanically stressed grain boundaries, which should lead to a better understanding of local damage caused by hydrogen. The aim is for the prediction model to require less materials data while at the same time better accounting for hydrogen-induced crack formation and propagation on the microscale.
The project plan envisages that the HyLife model will be directly applied in the ASME B31.12 and ISO 11114-4 standards for the design of components, thereby increasing safety and efficiency in the hydrogen economy.
Fraunhofer Institute for Mechanics of Materials IWM
