Retarding of Precipitation Hardening of Al-Cu Alloy by Cadimium Addition

Abstract

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

Keywords

• precipitation hardening retarding
• cd alloy
• vacancies trapping