Cryogenic Fracture Behavior of 316LN in Magnetic Fields up to 14.6 T
Some of the proposed magnet case alloys for the International Thermonuclear Experimental Reactor (TIER) are metastable austenitic stainless steels. The case will be subjected to high loads and can be as much as 100 mm thick in some proposed designs. Case assembly will probably require thick section welding with its attendant chemical inhomogeneity. Even alloys that are thermally stable with respect to martensitic transformation can, under these conditions of high stresses, cryogenic temperature, and high magnetic fields, undergo transformation. Previous work at 8 T has shown a measurable magnetic field effect on the 4.2 K tensile and fracture toughness properties of AISI300 series metastable austenitic stainless steels. Thus, it is important to understand how these alloys will behave under conditions of high magnetic fields and cryogenic temperature, particularly at the higher magnetic fields that will be used in ITER. 4.2 K data for 316LN indicates that the change in fracture toughness is not monotonic. It initially decreases and then later increases with applied field.
KeywordsFracture Toughness Applied Magnetic Field High Magnetic Field Cryogenic Temperature International Thermonuclear Experimental Reactor
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