Diffusion of copper along the grain boundaries in aluminum

The grain boundary diffusion (GBD) of copper in aluminum is investigated in the range t = 300?400°C. Investigations were performed on a scanning electron microscope equipped with an attachment for electron probe X-ray microanalysis. The triple product sδD _gb (where s is the segregation coefficient, δ is the width of the grain boundary, and D _gb is the GBD coefficient) was calculated by the Fisher criterion using two methods (namely, the copper concentration in the grain boundary, depending on the penetration depth, was determined and the angles in the vertex of the concentration profile was measured using an optical microscope). In the first case, sδD _gb was 5.1 × 10^?11 exp(?102/(RT)) m³/s; in the second case it was 1.4 × 10^?11 exp(?94/(RT)) m³/s. The obtained results are compared with innumerous literature data.