Effects of Ag on the age hardening response and intergranular corrosion resistance of Al-Mg alloys

Highlights: • The distribution, size and type of precipitates changed by Ag addition in Al-Mg alloys. • The phase structures of the precipitates in Al-Mg-Ag alloys were discussed in detail by TEM and HAADF-STEM. • The mechanical properties and corrosion resistance of Al-Mg alloys were both improved by alloying Ag. -- Abstract: Effects of Ag on age hardening response and intergranular corrosion resistance of Al-Mg alloys have been examined in this research. In the aging process, Ag addition can promote the formation of numerous fine-scale rod-like T-Mg₃₂(Al, Ag)₄₉ phases and granulate-shaped β″-(Al, Ag)₃Mg phases which distributed in the matrix uniformly. These dispersed particles enhanced the age hardening response conspicuously. Additionally, Ag can also inhibit the formation of the β phase (Al₃Mg₂) along the grain boundary and raised the corrosion potential E_corr of Al-Mg alloys. As a result, the intergranular corrosion resistance of Al-Mg alloys was improved by the addition of Ag.