Age hardening behaviour and microstructure of Al-Ag-(Sc) alloys

The age hardening behaviour and microstructure of Al-Ag-(0.2Sc) alloys were investigated. The results indicate that small addition of Sc can enhance the age hardening response of the Al-Ag alloy and prolong the time taken to the ageing peak. TEM observations show that the small addition of Sc results in a refinement of the distribution of γ′ precipitates. The mechanism by which trace Sc affect the microstructure is to reduce the ledge density of γ′ precipitates.