Superior strength and ductility in a low density duplex steel studied by in situ neutron diffraction

A low density, high strength medium-Mn steel was processed to produce a bimodal duplex microstructure consisting of coarse grained γ-austenite with fine δ-ferrite grains decorating the boundaries. Using combination ex situ analysis and in neutron diffraction, deformation mechanisms lattice strains within each phase were identified for specimens undergoing uniaxial tension during room elevated temperature loading up 473 K. The coarse-grained stacking fault energy deformed by dislocation glide, providing work hardening ductility. Simultaneously, produced an yield strengthening via composite reinforcing mechanism. Neutron diffraction reveals that reduction at temperatures is due strength. resulting 1200 MPa ultimate 0.3 ductility achieved this microstructurally engineered exceeds typical hot worked steels.