Mesoscale damage behavior and meso-macroscale correlation of low-cycle fatigue in Z2CND18.12N austenitic stainless steel

A low-cycle-fatigue damage behavior in Z2CND18.12N austenitic stainless steel is mainly studied at mesoscale, focusing on the correlation with that at macroscale. The variations of local misorientation in electron backscatter diffraction, ΔM_L, first increased with cyclic loading, then decreased to the minimum, and finally increased significantly, with <110> and <111> orientations having higher values than <100>. This evolution was positively correlated with the fraction of multiple slips and maximum von Mises stress, and negatively with the plastic-strain amplitude at macroscale in experiments and mesoscale in crystal-plasticity finite-element modeling. A ΔM_L model is proposed based on the dislocation evolution and slip mode.