Precipitate strengthening is a major strengthening mechanism for aluminum alloys, and thus the evolution of precipitates during service have received great attention, especially during the process of plastic deformation.However, the evolution of precipitates during the fatigue has not been extensive studied.The dissolution of small Al3Sc precipitates in an Al-Mg-Sc alloy after fatigue deformation has been proposed to be associated with particle shearing deformation caused by partially reversible to-and-for motion of glide dislocations.