Cyclic hardening/softening and deformation mechanisms of a twip steel under reversed loading

Push-pull tests at fixed plastic strain amplitude or stress were run on a TWIP steel, and followed by TEM observations, to analyze its cyclic behavior in relation with the deformation mechanisms. The kinematic isotropic components of flow measured throughout whole hardening/softening stages, their evolution cumulated was compared those tension. rise internal found responsible for initial hardening, but this reached most 50% stress, as nearly 70% Special constitutive equations identified capture these evolutions, well transition from hardening softening. Both slightly decrease during softening stage, whose origin is discussed, based observations peak amplitude, after present measurements combined previous study twinning/detwinning kinetics push-pull same steel [29], suggest that under loading, mechanical twinning cannot be significant intragranular nature (or “dynamic Hall-Petch effect”), rather contributes back intergranular origin.