Work hardening associated with ɛ-martensitic transformation, deformation twinning and dynamic strain aging in Fe–17Mn–0.6C and Fe–17Mn–0.8C TWIP steels

The tensile properties of carbon-containing twinning induced plasticity (TWIP) steels and their temperature dependence were investigated. Two steels with carbon concentrations of 0.6% and 0.8% (w/w) were tensile-tested at 173, 223, 273, 294, and 373 K. Three deformation modes were observed during tensile testing: ɛ-martensitic transformation, deformation twinning, and dynamic strain aging. The characteristic deformation mode that contributed to the work hardening rates changed with the deformation temperature and chemical compositions. The work hardening rate in the carbon-containing TWIP steels increased according to the deformation modes in the following order: ɛ-martensitic transformation > deformation twinning > dynamic strain aging.

► ɛ-Martensitic transformation gives work hardening rates of approx. 4 GPa.
► Twinning deformation gives work hardening rates of approx. 3 GPa.
► Dynamic strain aging gives work hardening rates of approx. 2.3 GPa.
► The contribution to work hardening rates are ɛ > twinning > dynamic strain aging.