Research progress in microalloying of Al-Zn-Mg series aluminum alloys

Al-Zn-Mg series aluminum alloys have important applications in aerospace, transportation etc, for their excellent properties of low density and high strength. Further optimizing the microstructure to obtain higher mechanical properties and better corrosion resistance is the development direction of Al-Zn-Mg alloys. Microalloying has become an important means of improving the properties of aluminum alloys, owing to the limited space for alloy composition optimization and heat treatment processes improvement. The effects of microalloying elements on the mechanical properties, hot deformation behavior and corrosion resistance of Al-Zn-Mg alloys were briefly summarized, focusing on the different effects of the second phase particles formed by microalloying elements in different process stages, such as effectively refine grains and strongly hinder the movement of dislocations. The effects of pin grain boundaries, sub-grain boundaries and inhibiting recrystallization during hot deformation were discussed. The internal mechanism of improving the corrosion resistance of the alloy was explained. In addition, the further research direction of microalloying of Al-Zn-Mg aluminum alloy was prospected, understanding the interaction mechanism of microalloying elements and dual alloying-microalloying elements to realize the precise and accurate addition of microalloying elements will be one of the main research contents in the future. Clarifying the regulation effect of microalloying elements on deformation structures and dislocation configurations during hot working will provide a reference for improving the corrosion resistance of alloys