Age-hardening characteristic of an Al-Zn-Mg-Cu alloy produced by spray deposition

Al-10.8Zn-2.8Mg-1.9Cu alloy was synthesized by spray atomization and deposition technique. GP zones and age-hardening process in the alloy were investigated using high-resolution electron microscopy (HREM), selected area diffraction (SAD), and differential scanning calorimetry (DSC) analysis. The results indicated that spray deposition process accelerated the aging kinetics of the alloy at an aging temperature of 120°C, thereby reducing the peak aging time to 16 h. GPI and GPII are the two types of zones that are major precipitates for the alloy under peak-aged condition. The precipitation sequence for the alloy is also discussed.