Influences of Ag Addition on the Microstructure and Mechanical Properties of Al-4Mg Alloy

In this study, the influence of Ag on the microstructures, precipitation behavior and mechanical properties of the Al-4Mg alloy are investigated. For the as-cast alloys, Ag can reduce the dimension of the precipitates and promote the precipitation of numerous fine-scale AlMgAg particles. In the aging process, Ag promotes the precipitation of nanoscale MgAg phase and T-Mg(32)(Ag, Al)(49) phase, which improves the aging hardening response of the alloy. At the peak-aged stage of 210 °C, the ultimate tensile strength of the Ag-bearing alloy is 280 MPa, and the yield strength is 200 MPa, which is much higher than that of Ag-free alloy.