Materials Safety for Hydrogen Gas Embrittlement of Metals in High-Pressure Hydrogen Storage for Fuel Cell Vehicles

Materials safety and selection for the application of metals in high-pressure hydrogen storage of fuel cell vehicles were introduced based on the hydrogen gas embrittlement (HGE) examinations using the materials testing equipment. Testing steps are as follows; the 1^st step is the tensile test in high-pressure hydrogen by slow strain rate technique to evaluate the effect of hydrogen and divide the materials into five categories based on stress-strain curves. The materials of type III, IV and V are picked up and their yield points and ultimate tensile strengths are collected. The 2^nd step is the fracture mechanics test to obtain K_ICs and K_IHs of type III, IV and V materials. The materials of type IV and V are considered to be applicable as usual. The 3^rd step is the crack growth test to obtain the fatigue crack growth data. A special consideration of HGE is taken for the design of the equipment with limited operation period or cycles for the materials of type III. The issue of the K_th’s reproducibility remains unresolved, which calls another testing method and design concept. Candidate materials are then nominated following the procedure of materials selection.