Effects of Aging Process on the Microstructure and Anti-Corrosion Properties of Al-Zn-Mg-Sc-Er Alloys

Al-Zn-Mg alloys are aluminum alloys that can be strengthened through heat treatment.Investigating the effects of various alloy aging processes on the microstructure and properties is one of the primary research directions in aluminum alloy studies.In this study， the effects of different aging processes on the mechanical properties and corrosion resistance of Al-Zn-Mg-Sc-Er alloys were investigated based on roomtemperature tensile tests， exfoliation corrosion tests， polarization curves， electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM).Results showed that after treatment with aging schedules T6， T7-LS and T7-SL， the room-temperature tensile properties of Al-Zn-Mg-Sc-Er alloys decreased sequentially， while the exfoliation corrosion ratings were EA， P and N， respectively.Analysis of polarization curves and electrochemical impedance spectroscopy revealed that as the aging degree of the alloy increased，the corrosion current density decreased， and the charge transfer resistance during electrochemical corrosion increased， leading to improved corrosion resistance.The main factors affecting the corrosion resistance of the alloy were identified as the type， size， distribution of precipitates and the width of the precipitate-free zone (PFZ).