液体水素輸送・貯蔵用極低温材料の開発

Abstract

The major activities of the Cryogenic Materials Working Group (Task 10) in the WE-NET Program are introduced, placing an emphasis on the mechanical properties of the structural materials to be used for liquid hydrogen vessels. Mechanical tests were conducted mainly using newly designed and installed liquid hydrogen facilities. In stainless steels, the fracture toughness of the weld at cryogenic temperatures is greatly increased by employing high-energy-density welding such as laser or electron-beam welding. In aluminum alloys, the properties of the welds at low temperatures are drastically improved by applying friction-stir welding. In addition, some properties of titanium and its alloy, which are considered as candidate materials for liquid hydrogen pumps, were also examined. Other activities related to the materials for liquid hydrogen vessels, including mechanical tests in gaseous hydrogen, assessment of local fracture toughness in welds and formulation of the database, are also briefly introduced.