Composition and temperature dependence of tensile properties of austenitic FeMnAlC alloys

The effects of aluminium addition (0–4 wt.%) to Fe-26MnAl alloys and carbon addition (0.1 – 0.3 wt.%) to Fe-30Mn-1AlC alloys on tensile properties, especially tensile elongation, were investigated from room temperature to 4 K. The transformation of austenite to deformation twins during the tests was very beneficial in enhancing tensile elongation at cryogenic temperatures. The amount of deformation twins formed during plastic deformation was not the major factor for maximum elongation, but the optimum work hardening rate by the gradual formation of deformation twins played an important role. The maximum elongation peak shifted to lower temperatures with increased aluminium (5 aluminium wt.%), but moved to higher temperatures with increased carbon content (0.3 wt.%). The new flow equation σ = KϵNexp (Mϵ) was applied to calculate uniform elongations. The calculated values were in reasonable agreement with the measured values.