PRECIPITATION IN AL-ZN-MG(-AG) ALLOYS

Age-hardenable Al-Zn-Mg alloys offer adequate strength, workability and weldability and have been widely used in the aerospace industry. The addition of microalloying elements of Ag can enhance the hardening response of the Al-Zn-Mg alloys, but the microstructure of Ag-added alloys has not been detailed studied. In this thesis, the solid-state precipitates in the Al-Zn-Mg(-Ag) alloys are investigated in detail down to the atomic scale, using various electron microscopy techniques.