The aim of the present work is to prepare a set of Al-Cu alloys with slow
precipitation hardening by aging. Present work results can be utilized during the
importing or exporting of such alloys at solution treatment conditions. In order to
establish this aim, a set of Al-4%Cu alloys have been prepared in the laboratory to
investigate the effect of Cd-addition with the percentage varied from (0.1, 0.3 and
0.5) weight percentage. The prepared alloys with different Cd additions were
subjected to a natural aging up to 60 days after solution treatment. As a result, the
alloys showed an obvious retarding in the aging kinetics as the percentage of Cdadditions
increasing. This retarding was found to be due to the trapping of the
vacancies that resulted during the quenching step that resulted in delays of Gunier-
Preston zones precipitation. SEM has been used in monitoring of microstructure as
well as optical microscopy