Evolution of microstructure, mechanical properties and corrosion behavior of Al-4Mg-2Zn-0.3Ag (wt.%) alloy processed by T6 or thermomechanical treatment

Highlights: • TMT technology promoted the dynamic precipitation of nanoparticles. • Interaction between dislocations and precipitates improved strength of the alloy. • The intergranular microstructure of GBPs and PFZ can be ameliorated by TMT. The evolution of microstructure, mechanical properties and intergranular corrosion (IGC) resistance of the heat-treatable Al-Mg-Zn-Ag alloy processed by T6 or thermomechanical treatment (TMT) technologies are systematically investigated. The mechanical properties and IGC resistance are both improved by the TMT technology. The combination of pre-deformation with aging promotes the dynamic precipitation of nanoparticles and the formation of substructure. Consequently, the hardening effect of the alloy is improved. The intergranular microstructure of grain boundary precipitates and precipitate free zone can be ameliorated by optimizing of processing parameter of TMT technology, which greatly improve the resistance of IGC of the alloy.