Interdiffusion in the α solid solutions of Al-Cu-Zn system at 817K

Abstract

Interdiffusion experiments of Al-rich α Al-Cu-Zn alloys have been performed at 817K. The concentration profiles indicate that the diffusion distance of Zn is somewhat longer than that of Cu in these solid solutions. The diffusion paths show S-shaped curves. The formation of S-shaped diffusion paths is attributed to the difference between the diffusion distance of Cu and Zn. The direct interdiffusion coefficients D^Al_ZnZn, D^Al_CuCu are positive, and the indirect coefficients D^Al_ZnCu, D^Al_CuZn are negative. The four interdiffusion coefficients are not sensitive to the solute concentrations. The magnitudes of D^Al_ZnCu/D^Al_ZnZn and D^Al_CuZn/D^Al_CuCu, indicate that Cu and Zn atoms in the Al-Cu-Zn alloys have attractive force between each other.