In this paper, Al-10.8Zn-2.8Mg-1.9Cu alloy was synthesized by the spray atomization and
deposition technique. The microstructure and mechanical properties of the spray deposited alloy at
various aging conditions (T6, T73 and RRA treatment) were studied using high-resolution electron
microscopy, selected area diffraction, and tensile tests. The results indicate that the two types of GP
zones, GPI and GPII zones are major precipitates for the alloy under peak-aged condition. The peak
UTS and YS values achieved at an ageing temperature of 120 °C was 818 MPa and 793 MPa. Under
two-step aging condition, the GP zones and η’ are major precipitates for the alloy, the discontinuous
grain boundary precipitates are favorable to SCC resistance in over-aged condition, which reduces its
strength 58 MPa(about 7%) comparing to the peak-aged condition. RRA treatment decreased ultimate
tensile strength 25 MPa (about 3%) in values compared with the alloy at T6 condition.
