Tensile testing at the Extremely Low Temperature of 6K : Microstructure and Mechanical Properties of a Fe-Mn-Cr Steel

Materials with superior cryogenic strength and good ductility are increasingly in demand for resident friendly liquid-hydrogen (20K) storage tanks. Additionally, the space industry also requires materials that retain excellent mechanical properties at extremely low temperatures. However, testing such temperatures is highly limited due to difficulties achieving maintaining conditions, while providing adequate thermal insulation prevent heat transfer from surrounding environment. In this study, we present a novel tensile technique Fe-15Mn-13Cr-3Si-3Ni-0.1C (wt.%) steel temperature of liquid helium. To minimize use expensive helium, adopted method injecting helium vapor set 6 K. The alloy has single face-centered cubic (FCC) structure large amount stacking faults after annealing treatment. Fe-Mn-Cr exhibited ultimate 1200 MPa 35% 6K. Moreover, compared room tests, discontinuous plastic flow, i.e. serrated occurred temperature.