Liquid Hydrogen Aerospace Application - Material Requirements & Limitations

The application of materials for liquid hydrogen tankage in aircraft application combines complex aspects for proper selection of candidate materials:

• general requirements for aircraft materials
• safety issues w.r.t. hydrogen and its failure modes
• cryogenic temperatures down to 20K
• hydrogen compatibility both in static, cyclic and sustained loading

These issues have been solved up to now only for cryogenic space tankage with limited life and specific requirements or ground support equipment where high margins are applied without focus on mass saving. Applications for aircraft combine long life and fatigue demonstration in combination with all mentioned aspects.

Selected candidate materials have to be assured without ductile to brittle behavior in the cryogenic regime and hydrogen embrittlement leading to brittle fracture or accelerated fatigue and crack growth. In addition physical properties may have to be considered in combination of different material combinations required from overall system aspects. The presentation is limited to metallic materials without insulation aspects.