An Fe-17Mn-0.6C steel with ultrafine elongated grain structure was successfully produced utilizing a multi-pass caliber-rolling process at 773 K. The uniform elongation of the developed steel was not severely degraded although its strength was greatly enhanced, leading to superior tensile properties. The result contrasted with most ultrafine-grained metals, including C-free TWIP steels, reporting the critical loss of uniform elongation. The peculiar phenomenon in the present work was attributed to the high work hardening capacity of C-added TWIP steels with the submicrocrystalline structure caused by dynamic strain aging, deformation twinning, and formation of stacking faults even after strong grain refinement.
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