Low-temperature diffusion in A1–7 wt. % Mg and A1–4 wt. % Cu alloys

Combined electron microscopy and electron energy analysis has been used to measure composition gradients near grain boundaries in aged Al-7 wt. % Mg arid A1–4 wt. % Cu alloys. The results show that the model due to Aaron and Aaronson (1968) describes satisfactorily the grain boundary precipitation process. Analysis of the development of the composition profiles associated with this precipitation has enabled low-temperature diffusion coefficients to be determined.