Effect of Zn/Mg and Cu/Mg on microstructure and properties of Al-xZn-3.0Mg-yCu-0.2Zr rolled aluminum alloy

Effect of Zn/Mg and Cu/Mg on microstructure and properties of Al-xZn-3.0Mg-yCu-0.2Zr rolled aluminum alloy was studied by XRD analysis, hardness and electric conductivity test, tensile test and intergranular corrosion experiments. The results show that for rolled aluminum alloy with compositon of Al-xZn-3.0Mg-yCu-0.2Zr, the increase of Zn/Mg and Cu/Mg values in the alloy can introduce dislocation into the alloy and promote recrystallization of the alloy. Increasing Zn to a certain extent has a strong hardening effect on the alloy, but when the Zn content rises above the solid solubility, the strength and toughness decrease. In addition, the increase of Zn is disadvantageous to the alloy's resistance to intergranular corrosion. The increase of the Cu/Mg value decreases the strength and the hardness, but the toughness is improved. In addition, the increase of Cu/Mg value will increase the resistance to intergranular corrosion of the alloy.