Effect of delayed aging on mechanical properties of an Al-Cu-Mg alloy

The effect of delayed aging on mechanical properties is characteristically found in Al-Mg-Si alloys. "Delayed aging" refers to the time elapsed betwee n solutionizing and artificial aging. Delayed aging leads to inferior prope rties. This effect was investigated in an Al-Cu-Mg alloy (AU2GN) of nominal composition Al-2Cu-1.5Mg-1Fe-1Ni as a function of delay. This alloy also s howed a drop in mechanical properties with delay. The results are explained on the basis of Pashley's kinetic model to qualitatively explain the evolu tion of a coarse precipitate structure with delay. It is found that all the results of delayed aging in the Al-Cu-Mg alloys are similar to those found in Al-Mg-Si alloys.