MECHANICAL PROPERTIES OF FRICTION STIR WELDED 5083 ALUMINUM ALLOY AT CRYOGENIC TEMPERATURES (STUDY ON LOW TEMPERARURE MATERIALS USED IN WE-NET 20)

摘要

5083 aluminum alloy is one of possible candidate materials for the liquid hydrogenstorage, since there are a lot of applications of 5083 for liquid natural gas (LNG)storage, such as LNG tanks and LNG ship carriers. Recently, we have clarified thatfracture toughness of the weld metals prepared by conventional large current metalinert-gas (LC-MIG) arc welding drastically decreases at temperatures below 77Kincluding 20K of liquid hydrogen. In order to improve the fracture toughness of theweld metals, it is necessary to refine their microstructures. Friction Stir Welding (FSW)is one of possible solution for their usage since there are many reports on finemicrostructure in welding part of an aluminum alloy with the FSW.We report microstructural characteristics and various mechanical properties atcryogenic temperatures of the FSW and the LC- MIG welding.