Current On-Tank-Valves (OTV) are used in hydrogen applications for pressure ranges up to 700/900 bar. In the automotive industry, the materials currently used for such valves are aluminium 6061 T6 or stainless steel (1.4435, 1.4475). The OTV is a complex component that requires long machining times and a large number of special tools. To achieve the required tightness with hydrogen, complex machining cuts are required, which currently make the valve a relatively expensive component. High-strength Al-Sc alloys could render stainless steel variants redundant if the corrosion resistance is sufficient. For this purpose, various Al-alloy series were tested to which different contents of up to 0.3 % Sc were added. The hardening curves were plotted for different temperatures and correlated with the corresponding mechanical tests. The alloys were characterised with hardness measurements, tensile tests and corrosion tests. Two production approaches are put into perspective: forging and additive manufacturing. For the first special attention was put to the variation of the alloy AlMg4.5Mn and its optimization. For the second, higher alloyed Al-Si-Sc alloys are in the focus, as rapid solidification alloys form a modified microstructure. By characterising the materials, transferring them to simulation models and developing design guidelines, the foundations are laid for technology transfer to other applications of these materials.

The work was performed in the project AluScaL in collaboration with German Aerospace Center, Anleg GmbH, Gränges Powder Metallurgy GmbH, Rosswag GmbH, Leiber Group GmbH, Gühring KG and the associated partners Rio Tinto Alcan International, RECARO Aircraft Seating GmbH & Co. KG and Liebherr-Aerospace Lindenberg GmbH. The project was funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWI 03LB3032G)