Metastable Austenites in Cryogenic High Magnetic Field Environments
The fracture behavior of austenitic stainless steels of differing stability, AISI310S, 304, and 304L, in a 4.2 K, 8T magnetic field environment are examined. 304L specimens with different amounts of work at different rolling temperatures are also examined. The different rolling conditions are used to produce stability differences independent of those inherent to chemistry differences. The application of an 8T magnetic field at 4.2 K leads to measured fracture toughness above and below that without an applied field in the metastable alloys, with the amount and direction of change a function of the stability of the alloy. Stable 310S alloy does not exhibit significant fracture toughness changes. This difference in fracture behavior is attributed to the enhancement of martensitic transformation about the crack tip during the fracture process in a magnetic field.
KeywordsFracture Toughness Martensitic Transformation Austenitic Stainless Steel Applied Magnetic Field Free Energy Difference
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