Retardation effect on sheet steel under a mixed I–II mode overload revealed by experiment, DIC and FEM methods

•A series of experiments was conducted to investigate the retardation mechanisms under mixed I–II mode overloads with loading angles 0, 30, 60 and 90°.•The overload retardation is weakened with the increasing mode II portion.•A combined model which considers the residual stress, plasticity-induced and roughness-induced crack closure effects was proposed.•This research can provide a reference for fatigue design and structural optimization of components.