Effect of liquid hydrogen exposure on mechanical and fracture properties of Ti-5Al-2.5Sn-ELI alloy in vacuum annealed condition

Ti-5Al-2.5Sn is an extra low interstitial (ELI) grade titanium alloy used in spherical gas bottles submerged in liquid hydrogen (LH2) tanks at cryogenic temperature (20 K). It is essential to study the effect of LH2 exposure on the mechanical and fracture properties of the alloy. The impact of LH2 on the fracture toughness and other mechanical properties, such as tensile properties, impact strength, and notch tensile strength (NTS) of the alloy Ti-5Al-2.5Sn, has been studied at room and cryogenic temperatures. The results show that there was a marginal degradation in fracture toughness and ductility of the alloy due to LH2 exposure. However, fractography analysis revealed that the fracture morphology of the alloy exhibits a typical ductile mode of failure in the presence and absence of LH2.