Novel strategy of electroshock treatment for improving mechanical performances of Al–Zn–Mg–Cu alloy by edge dislocation increment

The application of high-strength Al–Zn–Mg–Cu alloy is seriously limited because of its poor ductility and fatigue property. In this work, an electroshock treatment (EST), which is an expeditious and inexpensive strategy, has been adopted to improve significantly the ductility and fatigue life of Al–Zn–Mg–Cu alloy without reducing its strength. After analyzing microstructure evolution by multi-scale characterization, we demonstrated that the reason for improving the properties could be attributed to the homogeneous distribution of dislocations and dislocation increment, especially edge dislocation. An underlying mechanism that the cross-slip of screw dislocations was induced by the electron-dislocation scattering has been proposed to illustrate the phenomenon of microstructure evolutions.