Microstructure and mechanical properties of spray-deposited Al–10.8Zn–2.8Mg–1.9Cu alloy after two-step aging treatment at 110 and 150 °C

The microstructure and mechanical properties of a spray-deposited Al–10.8Zn–2.8Mg–1.9Cu alloy were investigated after a two-step aging treatment at 110 and 150 °C. The results indicate that GP zones and η′ are major precipitates for the alloy under the two-step aged condition. Discontinuous grain boundary precipitates are favorable for SCC resistance in the over-aged condition, which reduces its strength about 7% compared to the peak-aged condition.