Synchronous improvement of mechanical properties and corrosion resistance of novel heat-treatable 5xxx aluminum alloy by non-isothermal ageing

To overcome the trade-off between strength and corrosion resistance of traditional 5xxx aluminum alloys, in this paper, we investigate the evolution of microstructure, mechanical properties and intergranular corrosion (IGC) resistance of the novel heat-treatable Al-Mg-Zn-Ag alloy processed by isothermal or non-isothermal ageing (NIA). Results indicate that NIA can not only accelerate age hardening response greatly, but increase the number density of precipitates. Meanwhile, fast precipitation behavior in NIA process causes discontinuous distribution of grain boundary precipitates with finer-scale, which is instrumental in improving the IGC resistance. Hence, the strength and corrosion resistance of Al-Mg-Zn-Ag alloy are improved synchronously.