TENSILE BEHAVIORS OF AUSTENITIC STAINLESS-STEELS AT CRYOGENIC TEMPERATURES

The authors have examined the effect of strain rate on the tensile behavior of austenitic stainless steels in liquid helium. They observed similar flow curves of the materials in Be I as well as He II. They also measured some temperature rise of the specimens during tensile deformation. The serrated deformation was associated with the temperature rise and was dependent on the strain rate. It is presumed that the transition from discontinuous deformation to smooth one corresponds to the transition of heat transfer behavior between the specimen surface and the surrounding liquid helium. It is found that the martensitic transformation of austenitic stainless steels has conspicuous influence on the tensile behaviors and the temperature rise of the specimens.