Interdiffusion in the .ALPHA. solid solution of Al-Cu-Mg system

Interdiffusion experiments of Al-rich alpha Al--Cu--Mg alloys have been performed in a temperature range between 753-833K. The concentration profiles indicate that the diffusion distance of magnesium is somewhat longer than that of Cu in these solid solutions. The diffusion paths show S-shaped curves. The interdiffusion coefficients D exp Al sub CuCu , D exp Al sub CuMg , D exp Al sub MgMg and D exp Al sub MgCu are positive, and not so sensitive to the solute concentrations. The temperature dependence of D exp Al sub CuCu , D exp Al sub CuMg , D exp Al sub MgMg and D exp Al sub MgCu is expressed. Positive interaction parameters epsilon exp (Cu) sub Mg and epsilon exp (Mg) sub Cu indicate that Cu and Mg atoms in the Al--Cu--Mg alloys have the repulsive force to each other. Graphs. 21 ref.--AA