Partially-recrystallized ferrite grains and multiple plasticity enhancing mechanisms in a medium Mn steel

Abstract

We report initial and deformation microstructures of a Fe-6Mn-0.15C-1.5Si-1Al (wt%) medium Mn steel having an ultrafine duplex microstructure of ferrite and austenite. The cold-rolled and annealed material shows partially recrystallized ferrite grains. The ferrite grains contain screw dislocations formed by dislocation rearrangement upon recovery of deformed martensite. The cold-rolled and annealed material shows the activation of multiple plasticity enhancing mechanisms such as deformation twinning and deformation-induced martensitic transformation. Both partially recrystallized ferrite grains and multiple plasticity enhancing mechanisms could contribute to high yield strength and high strain hardening of the investigated medium Mn steel.