Effects of Cu and Mg contents on mechanical properties of Al-xCu-yMg-0.6Ag alloy

Al-xCu-yMg-0.6Ag alloys with different Cu and Mg content were prepared by ingot metallurgy and thermomechanical treatment.The effects of Cu and Mg contents on the microstructures and mechanical properties of the alloys have been investigated using tensile testing,differential scanning calorimetry(DSC),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).It has been shown that increasing Cu and Mg content improves the aging hardness and tensile strength of Al-Cu-Mg-Ag alloy.The coherent plate-like Ω phase and a small amount of θ/ phase are the predominant hardening phases in the Al-xCu-yMg-0.6Ag alloys at peak-aged stage at 185 ℃.Increasing Cu content improves the density of the Ω phase after aging treated to peak-aged stage.Increasing Mg content accelerates the aging hardening process of the alloys and decreases the size of Ω phase.