Interdiffusion coefficients in the face-centered cubic phase of this alloy system were determined under pressures of between 0.101 and 2800MPa, and temperatures ranging from 815 to 860C. It was found that the direct coefficients, DCuCuAl and DZnZnAl, were positive and the indirect coefficients, DCuZnAl and DZnCuAl, were negative. The diffusion coefficients decreased with increasing pressure (table 28), and the activation energies for interdiffusion and impurity diffusion increased with pressure. The ratio of the activation volume to the molar volume of Al was between 0.96 and 1.05. It was concluded that the diffusion of Cu and Zn in this alloy system occurred mainly via a mono-vacancy mechanism.
T.Takahashi, T.Yamane, T.Yamamoto, H.Araki, Y.Minamino, Y.Miyamoto: Zeitschrift für Metallkunde, 1994, 85[7], 492-7
Table 28
Interdiffusion in the Al-Cu-Zn System
as a Function of Temperature and Pressure
Pressure (MPa) | Temperature (K) | Coefficient | Value (m2/s) |
0.101 | 815 | DCuCuAl | 1.4 x 10-13 |
0.101 | 830 | DCuCuAl | 2.0 x 10-13 |
0.101 | 845 | DCuCuAl | 2.8 x 10-13 |
0.101 | 860 | DCuCuAl | 4.0 x 10-13 |
0.101 | 815 | DCuZnAl | -3.6 x 10-15 |
0.101 | 830 | DCuZnAl | -2.1 x 10-15 |
0.101 | 845 | DCuZnAl | 6.8 x 10-15 |
0.101 | 860 | DCuZnAl | -5.2 x 10-15 |
0.101 | 815 | DZnCuAl | -8.0 x 10-14 |
0.101 | 830 | DZnCuAl | -7.6 x 10-15 |
0.101 | 845 | DZnCuAl | -2.5 x 10-13 |
0.101 | 860 | DZnCuAl | 5.6 x 10-13 |
0.101 | 815 | DZnZnAl | 4.2 x 10-13 |
0.101 | 830 | DZnZnAl | 5.9 x 10-13 |
0.101 | 845 | DZnZnAl | 7.6 x 10-13 |
0.101 | 860 | DZnZnAl | 1.2 x 10-12 |
2000 | 815 | DCuCuAl | 6.6 x 10-15 |
2000 | 830 | DCuCuAl | 9.6 x 10-15 |
2000 | 845 | DCuCuAl | 1.4 x 10-14 |
2000 | 860 | DCuCuAl | 2.0 x 10-14 |
2000 | 815 | DCuZnAl | 1.3 x 10-16 |
2000 | 830 | DCuZnAl | 1.7 x 10-15 |
2000 | 845 | DCuZnAl | -2.0 x 10-15 |
2000 | 860 | DCuZnAl | -2.7 x 10-15 |
2000 | 815 | DZnCuAl | -9.8 x 10-16 |
2000 | 830 | DZnCuAl | 1.2 x 10-14 |
2000 | 845 | DZnCuAl | 1.3 x 10-14 |
2000 | 860 | DZnCuAl | -1.4 x 10-14 |
2000 | 815 | DZnZnAl | 2.5 x 10-14 |
2000 | 830 | DZnZnAl | 3.5 x 10-14 |
2000 | 845 | DZnZnAl | 5.0 x 10-14 |
2000 | 860 | DZnZnAl | 7.5 x 10-14 |
2800 | 815 | DCuCuAl | 2.0 x 10-15 |
2800 | 830 | DCuCuAl | 3.1 x 10-15 |
2800 | 845 | DCuCuAl | 4.1 x 10-15 |
2800 | 860 | DCuCuAl | 6.7 x 10-15 |
2800 | 815 | DCuZnAl | -1.7 x 10-17 |
2800 | 830 | DCuZnAl | 2.4 x 10-16 |
2800 | 845 | DCuZnAl | -5.7 x 10-16 |
2800 | 860 | DCuZnAl | -1.6 x 10-16 |
2800 | 815 | DZnCuAl | -3.2 x 10-15 |
2800 | 830 | DZnCuAl | 8.6 x 10-15 |
2800 | 845 | DZnCuAl | -2.8 x 10-15 |
2800 | 860 | DZnCuAl | -7.5 x 10-15 |
2800 | 815 | DZnZnAl | 7.7 x 10-15 |
2800 | 830 | DZnZnAl | 1.2 x 10-14 |
2800 | 845 | DZnZnAl | 1.4 x 10-14 |
2800 | 860 | DZnZnAl | 2.7 x 10-14 |