Effects of magnetic field on tensile behavior at 4 K of alloys 304 and 310

Experiments were conducted to assess the effects of a steady magnetic field on the austenite stress-strain characteristics at 4 K. Wire specimens (0.64-mm dia) of both a stable Fe-26Cr-20Ni (AISI 310) and metastable Fe-18Cr-9Ni (AISI 304) were measured. A 7-T magnetic field was produced by a split-pair NbTi superconducting magnet with radial access ports and the field was applied perpendicular to the tensile specimen axis. Tests were conducted at 4 K with the field off, with the field on, and with the field switched on and off after prescribed amounts of plastic deformation. The Young's modulus, tensile yield strength and tensile stress-strain curves were measured. The results are summarized here: (1) during magnetic field on/off experiments, no change in austenite flow strength of either alloy was observed from the application or absence of a 7-T field and (2) there was no detectable effect of a constant 7-T magnetic field on the yield strength and Young's modulus of either alloy. However, the specimen-to-specimen yield strength data scatter was large and the application of magnetic field would not necessarily produce changes of flow strength in excess of the data scatter. Discussion is also presented on magnetic field effects on discontinuous yielding and cold worked alloys