Examination of mechanical behaviour of aged duplex steel using X-ray and neutron diffraction methods

The parameters characterizing the elastoplastic mechanical behaviour of each phase in austeno-ferritic duplex stainless steels were determined using X-ray and neutron diffraction during a uniaxial tensile test. The elastoplastic self-consistent model was used to predict the evolution of the lattice elastic strains during loading and to identify the critical resolved shear stresses and work hardening parameters of the material. The effect of ageing treatment on the elastoplastic behaviour of both phases was also studied. It was found that thermal ageing of austeno-ferritic steel caused microstructural transformations and consequently a significant increase of the hardness of ferrite, while the mechanical properties of austenite remained practically unchanged.