Effects of Ag content on microstructures and properties of Al-Cu-Mg alloy

The effects of Ag content on the mechanical properties and microstructures of Al-Cu-Mg alloy have been studied by Wicker hardness test (HV), room temperature tensile properties, optical microscopy (OM) and transmission electron microscopy (TEM). The results show that as the increase of Ag content, the yield strength and the tensile strength are improved to some extent, and the plasticity is decreased gradually, but it maintains at a high level. In addition, the hardening rate is accelerated, and the peak hardness is increased. The main strengthening phases in Al-Cu-Mg alloy without Ag is theta ' phase. However, in the alloy with trace Ag it is Omega phase. The number of Omega phase increases gradually with Ag content increasing. The trace Ag promotes the precipitation of Omega phase.