Abstract
? 2022 Elsevier B.V.The influence of T6 heat treatment process and Cu and Ag alloy elements as variables on the microstructure, mechanical properties and intergranular corrosion (IGC) performance of Al-Mg-Zn-Cu-Ag alloy was systematically studied. The results show that there is a small improvement in the mechanical properties and IGC resistance of the 0.50Cu (wt%) alloy compared to the 0.25Cu (wt%) alloy when the peak ageing temperature is reached at 180 °C. At a constant value of Cu element content, with the addition of Ag element and its increasing content, a large number of nanoscale dispersive phases precipitated in the alloy crystals, and their number density also increased. This resulted in a substantial improvement in the mechanical properties (including strength and hardness) of the alloy. Both the 0.50Cu-0.72Ag (wt%) alloy and the 0.50Cu (wt%) alloy reached peak aging at 36 h at 180 °C. At this time, the 0.50Cu-0.72Ag (wt%) alloy showed an increase in hardness of 46.4 MPa, YS of 148.3 MPa, and UTS of 103.6 MPa compared to the 0.50Cu (wt%) alloy. The intergranular corrosion performance (IGC) of the alloy is related to the different aging states, with the solid solution state having the best IGC resistance, the under-aged and over-aged states being the next best, and the peak aging state having the worst IGC resistance. The addition of Ag improves the IGC resistance of the alloy to a small extent, and the weight loss of alloy 5 containing 0.72Ag (wt%) is reduced by 27.2 mg/cm2 compared to alloy 3 containing 0.18Ag (wt%) at T-36 peak aging.
NSTL
Elsevier